Whats meant by flash lines & polish
Discussion
From what i understand, the flash lines are the edges of the panels when they are popped out of the moulds. You would definately have to have these flattened and polished at some point during the build. From what ive heard its quite a messy and potentially painful process (sharp edges/fibreglass bits).
Hi Mark
It means to remove the marks left from when the body was removed from the moulds. The moulds are in sections so they leave flash lines when removed. If your having the bodywork sprayed then you can leave it for the bodyshop to do as part of the preparation for painting.
Regards Dave
It means to remove the marks left from when the body was removed from the moulds. The moulds are in sections so they leave flash lines when removed. If your having the bodywork sprayed then you can leave it for the bodyshop to do as part of the preparation for painting.
Regards Dave
Even if you spray-finish Mark, the moulding will still have a gel-coat surface (grey coloured for paint-planned cars I think). The painted route will require some trimming/flatting/finishing of the raw grey mould just to get the pre-fit stage acceptable (body lines/apertures etc). This all before the detailed paint-preparation process begins.
If you are going for painted make sure your bodyshop choice uses water-based materials and fully understands GRP refinishing......many who claim to, don't!
If you are going for painted make sure your bodyshop choice uses water-based materials and fully understands GRP refinishing......many who claim to, don't!
Edited by 738 driver on Saturday 28th March 17:43
Edited by 738 driver on Saturday 28th March 19:13
When you talk to the potential sprayers you will know they know what they are doing if they say the first thing they are going to do is bake the body.
Any GF work will have some air bubbles trapped in it somewhere. If the bubble is just below the surface it will pop when the body is heated. This is no problem as they can then deal with it when doing the body prep. What they don't want is for it to pop when they are oven drying the final coat.
Steve
Any GF work will have some air bubbles trapped in it somewhere. If the bubble is just below the surface it will pop when the body is heated. This is no problem as they can then deal with it when doing the body prep. What they don't want is for it to pop when they are oven drying the final coat.
Steve
Hmm......not too sure if modern refinishers would use that pre-bake technique Steve... Its a very 'old technology' method used on GRP in the days of cellulose and solvent based paints.(non of which should now be used on GRP). They did used to bake the panels full chat before prepping them. During the last 10-12 years, any of my ex-colleagues would have received the DCM for risking that process!
GRP refinishing should now be done using mainly water based materials (less shrinkage/attack on the solvent based polyester gelcoat/resin) and also baked using a very low/slow cycle. 30-35'C for 60 mins as opposed to 80'C for 20mins as used on steel (and previously on glassfibre). Remember these are panel temps recorded in the oven, the air temp is much higher than this...far more than the body should normally experience.
The problem is many smaller shops have not been able to afford to update their ovens from solvent to water born. (stainless steel/galvanised construction and double the airflow) So, they use the technique you mentioned to try and avoid the problems you also described...... potentially creating more long term issues. If you get a larger dry area between the layers (as opposed to the pinholes you mentioned) you can get quite large areas of spider-web like, hairline cracking... as the very hot air has to escape somewhere! As the mould cools at the end of a hot cycle
these cracks contract and are very difficult to spot. The damage is done though and you now have an area which is porus and able to absorb moisture from warm humid air. As you expect, when trapped under top-coats this leads to long-term issues, micro-blister, surface cracking etc,etc.
GRP does not like to be heated at all really and always ultimately shows this at the surface, usually several days/weeks later. Also, after many hours of painstaking preparation and alignment the last thing you want are ripples and distortion to appear just because of excess heating.
If you can find a good shop, a longish pre-prep bake at low temps would be ideal, even before the body is keyed. If I'm at the point of painting and the mould is less then six months old, a couple of hours at 30-35'C followed by DA sanding with 1000's is all that should be required to secure a long lasting basis for paint. The machine sanding will flatten/remove imperfections in the gel-coat as well as key the surface for a wet-on-wet refinish. With a maleable material like glassfibre less paint is better.
Its a shame really, but many potentially good bodyshops wont move on with technology and still insist on baking,priming,baking,painting,baking, polishing and then re-working their cock-ups. This very old-school process/mentality, along with suppressed labour rates are just a couple of the reasons many cant afford new equipment.....also why your nice motors get lost in their systems for weeks-on-end. (rant over)
Edited......for any potential insults to our Mentors.
rgds,
Dave.
GRP refinishing should now be done using mainly water based materials (less shrinkage/attack on the solvent based polyester gelcoat/resin) and also baked using a very low/slow cycle. 30-35'C for 60 mins as opposed to 80'C for 20mins as used on steel (and previously on glassfibre). Remember these are panel temps recorded in the oven, the air temp is much higher than this...far more than the body should normally experience.
The problem is many smaller shops have not been able to afford to update their ovens from solvent to water born. (stainless steel/galvanised construction and double the airflow) So, they use the technique you mentioned to try and avoid the problems you also described...... potentially creating more long term issues. If you get a larger dry area between the layers (as opposed to the pinholes you mentioned) you can get quite large areas of spider-web like, hairline cracking... as the very hot air has to escape somewhere! As the mould cools at the end of a hot cycle
these cracks contract and are very difficult to spot. The damage is done though and you now have an area which is porus and able to absorb moisture from warm humid air. As you expect, when trapped under top-coats this leads to long-term issues, micro-blister, surface cracking etc,etc.
GRP does not like to be heated at all really and always ultimately shows this at the surface, usually several days/weeks later. Also, after many hours of painstaking preparation and alignment the last thing you want are ripples and distortion to appear just because of excess heating.
If you can find a good shop, a longish pre-prep bake at low temps would be ideal, even before the body is keyed. If I'm at the point of painting and the mould is less then six months old, a couple of hours at 30-35'C followed by DA sanding with 1000's is all that should be required to secure a long lasting basis for paint. The machine sanding will flatten/remove imperfections in the gel-coat as well as key the surface for a wet-on-wet refinish. With a maleable material like glassfibre less paint is better.
Its a shame really, but many potentially good bodyshops wont move on with technology and still insist on baking,priming,baking,painting,baking, polishing and then re-working their cock-ups. This very old-school process/mentality, along with suppressed labour rates are just a couple of the reasons many cant afford new equipment.....also why your nice motors get lost in their systems for weeks-on-end. (rant over)
Edited......for any potential insults to our Mentors.
rgds,
Dave.
Edited by 738 driver on Sunday 29th March 09:17
Post edited Steve, I will have to stop evening posting after being up at 03.50....it really is the wrong end of the day to rant about the ex- trade!
Theres many a day I pitch up for work and feel 'very' old....sadly its 19 yrs before retirement when I can start to feel 'young again'.....some days I really look forward to it!
Theres many a day I pitch up for work and feel 'very' old....sadly its 19 yrs before retirement when I can start to feel 'young again'.....some days I really look forward to it!
Edited by 738 driver on Sunday 29th March 11:10
Edited by 738 driver on Sunday 29th March 13:10
How DO you paint an Ultima ? Finish the whole thing off and then mask it ? Or paint the prefitted panels first then rivet them to the chassis afterwards with all the associated distortion and consequential fileing of the gaps and scratches ! I used to paint all my rebuilds myself , one being a fibreglass Daimler Dart .I removed the old cellulose with a blowlamp , believe it or not ! [You can't use paint stripper on fibreglass] . I am not a " concours " man as such but I sold the daimler to a friend who then won the national Daimler concours with the car . Presumably you have to use etch primer or is it now illegal ? I haven't painted a car for 30 years now so am out of touch . The beauty of the Ultima body is that WHEN you scratch and file the body , the coloured gellcoat is so thick that you can rub out most of the damage especially the scratches . Unless you have an overwhelming desire to paint an Ultima or are an expert I don't think it's a wortwhile task ; but I am getting on !
Frank
Frank
Blowlamp certainly made me chuckle Frank but it obviously did the job well.
Does sort of undermine the 'dont overheat your Ultima fibreglass body advice though'!
We used to use thinners cloths on fibreglass stripping, thinners removes well-cured cellulose in a couple of minutes and over a short period, doesn't attack the gelcoat. I did our glorious leaders' Scimitre GTE for him in about 1986, took a couple of days to strip. Was then prepped and painted in high solids 2K material....looked really well when finished and still does to this day! (apparently it hasn't been out much though)
If you are painting an Ultima you could do it either way, I would really think it depends if its new build or repaint job...you would really be best to mask the latter. The only thing with masking is really the ally rivets should have acid etch applied to them whereas the glassfibre bits
need a misting of plastics primer...so etching the rivets could be quite time consuming. (nothing looks worse than flaking rivet paint.....looks like the car took part in a war)
If it were new build and this includes my proposed method, I'll fully fit everything but use skin pins/ small c/s self tappers initially..maybe every 3 or 4 inches. Once its all fully aligned properly and all the fixing holes drilled without tension/distortion, it can come off to be final painted. I'll most likely slow bake and final sand whilst its still in the temp fitted stage.
When you get a new mould it will probably still have quite a lot of release agent on the gelcoat. Now if the body is pre-coloured it will be covered in gloss wax polishes during the course of its life which also seals and protects the release agent. So whenever painting a GRP moulding its best to spend time and money on a good quality pre-paint panel-wipe.
This product removes wax and release agents, as good insurance I would usually do the whole moulding at least twice.....long before you go anywhere near it with abrasives or primers. If you dont and proceed to key it whilst still contaminated with wax/release agent, all that will happen is you will rub the contamination into the millions of tiny keying marks /scratches with the resulting loss of primer/paint adhesion.
Its all straightforward, logical stuff really, similar principles to home decoration.
Good preparation, product selection and immaculate house-keeping have always been and will remain the key elements to any refinishing success.
With your concours results you must have applied the same practices.
I'm still chuckling over the blow-lamp stripper antics!
My mate lost his Lotus Europa after he had completed a carb service on it....started it without the air-filters.. it spat back and set the minor fuel spillage alight......he legged it out of his wooden workshop, straight past his own fire extinguisher to phone the fire brigade. Apparently it took a good few hours for the remaining chassis, engine and box to cool down!
Does sort of undermine the 'dont overheat your Ultima fibreglass body advice though'!
We used to use thinners cloths on fibreglass stripping, thinners removes well-cured cellulose in a couple of minutes and over a short period, doesn't attack the gelcoat. I did our glorious leaders' Scimitre GTE for him in about 1986, took a couple of days to strip. Was then prepped and painted in high solids 2K material....looked really well when finished and still does to this day! (apparently it hasn't been out much though)
If you are painting an Ultima you could do it either way, I would really think it depends if its new build or repaint job...you would really be best to mask the latter. The only thing with masking is really the ally rivets should have acid etch applied to them whereas the glassfibre bits
need a misting of plastics primer...so etching the rivets could be quite time consuming. (nothing looks worse than flaking rivet paint.....looks like the car took part in a war)
If it were new build and this includes my proposed method, I'll fully fit everything but use skin pins/ small c/s self tappers initially..maybe every 3 or 4 inches. Once its all fully aligned properly and all the fixing holes drilled without tension/distortion, it can come off to be final painted. I'll most likely slow bake and final sand whilst its still in the temp fitted stage.
When you get a new mould it will probably still have quite a lot of release agent on the gelcoat. Now if the body is pre-coloured it will be covered in gloss wax polishes during the course of its life which also seals and protects the release agent. So whenever painting a GRP moulding its best to spend time and money on a good quality pre-paint panel-wipe.
This product removes wax and release agents, as good insurance I would usually do the whole moulding at least twice.....long before you go anywhere near it with abrasives or primers. If you dont and proceed to key it whilst still contaminated with wax/release agent, all that will happen is you will rub the contamination into the millions of tiny keying marks /scratches with the resulting loss of primer/paint adhesion.
Its all straightforward, logical stuff really, similar principles to home decoration.
Good preparation, product selection and immaculate house-keeping have always been and will remain the key elements to any refinishing success.
With your concours results you must have applied the same practices.
I'm still chuckling over the blow-lamp stripper antics!
My mate lost his Lotus Europa after he had completed a carb service on it....started it without the air-filters.. it spat back and set the minor fuel spillage alight......he legged it out of his wooden workshop, straight past his own fire extinguisher to phone the fire brigade. Apparently it took a good few hours for the remaining chassis, engine and box to cool down!
Edited by 738 driver on Sunday 29th March 20:30
Edited by 738 driver on Monday 30th March 16:11
The blowlamp is a true story . Moreover it was a very early Dart with extremely thin fibreglass door panels and wings but with about 6 layers of cellulose paint . The paint was as thick as the body in places ! The art was to run over the whole panel very quickly with the lamp until the paint started to fume and the you could start at the edge of the panel and peel off the whole lot in one go .This car had also been in an accident which had torn off the nose which fortunately had been kept . It was a fairly easy job to feather it from the inside and fibreglass it back on . You couldn't see the join . I used to finish with 1000 grade paper and then polish by hand with Brasso . In those days you could buy a gallon can of it ! I had the chassis sand blasted and metal sprayed , then I etched it and painted it . The engine was v8 funnily enough with a very long stroke and you could pull away in top with ease !
Frank
Frank
Ahhh..off topic I know but...
The Blowlamp thing...reminded me of the time I walked into car repair shop in Tewkesbury to find an old boy (of 40 years experience) with a ford high up on the ramps preparing to WELD a petrol tank still in the car!
When questioned about the risk, he said " Arrr... (chuckle) ..s'no problem wiv the tank topped to the brim with fuel! ....problem is when the younguns try this wiv the tank half full - BOOSH!" ...and then he flashed up the torch, turning back to his welding job!
...Needless to say I almost tripped over myself trying to get out of the garage (and Tewkesbury) at high speed!
Keith
The Blowlamp thing...reminded me of the time I walked into car repair shop in Tewkesbury to find an old boy (of 40 years experience) with a ford high up on the ramps preparing to WELD a petrol tank still in the car!
When questioned about the risk, he said " Arrr... (chuckle) ..s'no problem wiv the tank topped to the brim with fuel! ....problem is when the younguns try this wiv the tank half full - BOOSH!" ...and then he flashed up the torch, turning back to his welding job!
...Needless to say I almost tripped over myself trying to get out of the garage (and Tewkesbury) at high speed!
Keith
Mark,
Speak to Option 1 in Bromsgrove, they specialise only in GRP repairs and painting. Mainly on classic cars, Lotus, TVRs and the like but they have had good reviews from some Lotus lads I know.
http://www.option1sportscars.co.uk
Robin
Speak to Option 1 in Bromsgrove, they specialise only in GRP repairs and painting. Mainly on classic cars, Lotus, TVRs and the like but they have had good reviews from some Lotus lads I know.
http://www.option1sportscars.co.uk
Robin
During selection of your proposed Ultima Bodyshop, pay them a visit....but dont announce it. Try to just turn up and take a sneak-peek/casual inspection of their workshop, their housekeeping will usually tell you what you need to know.
The old 'mystery-shop/incognito audit' really can be an eye-opener in the refinishing industry. Many High-Marque, maindealer shops were the worst culprits, I used to find it an outrage that several MD's would not put their own family vehicles through their under-performing bodyshops, frequently recommending other independant repairers (local labour rates/repair times were standardized). You are quite justified though as you will be paying them a lot of money and in many instances be giving them full responsibility of the second-largest/most important purchase you have ever made!
That simple theory was etched across our whole workforce, if you worked on the latest £150'000 Ferrari this morning and are now working on a £450 Montego they both deserve the same high level of working respect. In many instances, to their respective owners, the Montego was of more relative importance than the Ferrari!
The old 'mystery-shop/incognito audit' really can be an eye-opener in the refinishing industry. Many High-Marque, maindealer shops were the worst culprits, I used to find it an outrage that several MD's would not put their own family vehicles through their under-performing bodyshops, frequently recommending other independant repairers (local labour rates/repair times were standardized). You are quite justified though as you will be paying them a lot of money and in many instances be giving them full responsibility of the second-largest/most important purchase you have ever made!
That simple theory was etched across our whole workforce, if you worked on the latest £150'000 Ferrari this morning and are now working on a £450 Montego they both deserve the same high level of working respect. In many instances, to their respective owners, the Montego was of more relative importance than the Ferrari!
in the build manual they say something about pinholes, so removing flash lines may also require filling up the gelcoat with gelcoat so be sure to order a liter for that purpose (that seems to be the minimum order quantity).
If you intend to paint the body later then the holes might be as well filled with anything else suitable.
If you intend to paint the body later then the holes might be as well filled with anything else suitable.
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