How do I fix this fiberglass?

[Kendo]

I'm repainting me Europa and got to the front trunk lid. Here are some pictures of what's under the paint. I have three questions about how to proceed. First, someone covered the lid with cloth glass, which printed through the paint, so I knew that going in. Questions:

1) How do you cover a large area with tissue? I only have about 10 minutes before the resin hardens. So, paint on the resin, lay down the glass, get it wet... How do you do it in time?

2) after a lot of sanding, the cloth glass still has little dots of primer between the threads. Should I sand until it's all gone? Or is, say primer covering less that 50% of the area good enough for laying on the covering glass tissue?

3) Those white blotches look an awful lot like  someone didn't wet the cloth enough when he put it down. Should I grind that out and fill it properly? I never noticed anything when it was painted. So it appears stable.

Many thanks. I'm sure I'll have lots more questions.

Ken

[Clifton]

Boat people would fair it out with epoxy.  Basically skim it with epoxy. It bonds better than the polyester resins typically used with fiberglass. You can get it with thickeners add or add your own.  West Systems is well known and great. Total Boat makes the same epoxies, just a little less expensive.

A few links
https://www.youtube.com/watch?v=Hajh5n39H8M

http://www.totalboat.com/product/totalfair/#pr-header-back-to-top-link

https://www.jamestowndistributors.com/userportal/search.do?refineType=1&sub_attr_name=Brand&refineValue=TotalBoat&refine=1&page=GRID&history=7u67ayl1%7Cother%7Crefine%7E1%5Epage%7EGRID%5Ecategory%7E589%5EprodPage%7E15%5EsubCategoryName%7EEpoxy%2BResin%5EcategoryName%7Ecat_203%5Euser_att_name0%7EUserType%5Euser_att_value0%7ENewUser

[Clifton]

I should have added. Polyester resigns shrink over time. Epoxy does not. If you skim with fiberglass resin (polyester) or do a fiberglass repair with fiberglass resin and it is not thick enough, the mat may show through later.  This vid is one of the product I put above. It is their premixed fairing epoxy.  https://www.youtube.com/watch?v=F7jZL5X6i00

[Kendo]

West Marine is my go-to epoxy for other jobs. So I know how good they are. But I'm concerned about adding epoxy to the car since polyester resins don't adhere well to it for later repairs. (I think I already did that early in my Europa ownership) I'd rather not be the DPO. Then again, I already repaired a crack in the trunk lid, and don't remember if I used epoxy or polyester resin. So, I might be my own Dreaded Current Owner. So, I might have to use epoxy resin anyway. Any idea how to test whether epoxy is on an area versus polyester?

[BDA]

Somebody else made the same mistake I did! I didn't actually do it, but I had a college buddy of mine do some body work for me and we both thought it would be a good idea to put a layer of the finest cloth over the body - the idea was that if you have an accident and you have all the fiberglass pieces, it's a lot easier to fix and having cloth makes it more likely that you'll keep all the pictures. As you saw, the weave bleeds through the paint almost no matter what you do.


You can sand it off and/or cover it with gauze. I would certainly get those areas that don't look like they had enough resin out and that means you'd have to fill those areas in. At that point, it might be worth it to sand it all off. It's your choice but I think you'll have a better surface if you get rid of the cloth first and then lay the gauze.


Ten minutes might be enough time to lay the gauze but you probably don't want to mix your resin so "hot". Use a little less hardner to give yourself more time. The really good fiberglass guys (not me) know how to gauge the temperature and humidity to mix their resin. Experiment with different amounts of hardner to see what gives you enough time and still hardens properly. Giving yourself too much time (not using enough hardner) will just make a mess and it will never really harden.


I think Clifton has the line on epoxy vs. polyester resin, and fairing. I have used plain bondo with good results (for thin thicknesses). I know that's somewhat of a sacrilege to some. A guy I new who was very good with fiberglass mixed his own filler with glass spheres and resin. That being said, it's probably better to use a product designed for that purpose.

[EuropaTC]

Hi Ken,

10 minutes working time for a resin doesn't sound right, I know you guys have warmer weather than over this side of the pond but even so, 10 minutes is rushing things. I would reduce the hardener or catalyst levels in your mix, you only need a few percent to set it off. For it to go off so quickly it wouldn't surprise me to find the resin is getting hot while curing, which isn't a good proposition in the long run. (expansion/contraction stresses left in the repaired area)

As for finishing, most folks use a very, very fine tissue for the outer layers. This is very thin, transparent in fact and wets out very easily. Typically I paint on some resin, drop the tissue on and then wet it out with a brush. I usually put two or three layers of tissue on and leave the last pass with a resin-rich layer. This gives a very solid finish with no bubbles and easily sands with 60/80 grit paper (used dry) to the right contour which you can smooth down with 240 grade.  You might get the odd pinhole at that stage but nothing that can't be dealt with using conventional stopper or even spray fillers.

You will have suppliers over there but for explanation's sake, this is the link to the tissue I use from my favourite supplier over here;

http://www.cfsnet.co.uk/acatalog/CFS_Catalogue__Surface_Tissue_359.html

Brian

[Clifton]

From what I see in the pics, you don't have cracks or crazing, just the mat showing through from too thin of a layer or resin over it. Just add a thicker layer of resin with epoxy and be done.  I wouldn't use poly resin for any repairs on old fiberglass, it's not worth taking a chance of a poor bond when epoxy bonds better, has almost twice the strength, better elongation and doesn't shrink showing mat later after it's painted. If you liked Westsystems epoxy, look at Totalboat specs. I looked at the technical specs of both. They were the same for the slow cure. You can get Total boat with pumps for about half the cost of West without pumps.

[Mike Surber]

If you want a nice smooth surface. That will stay that way. Never ever use woven cloth as your top layer. It will always bleed through. Even on fine hand layed bodies, the first layer to go in (after the jell coat has set) is a layer of mat. Then 2 or 3 layers of woven cloth. To put down veil over a fairly large area. Use a cheap very short nap paint roller (not sponge it'll melt. Just ask me how I know LOL). Roll on the resin (it can be sprayed on too if you have the right pressurized gun) then lay out the veil over it dry. Then go back over with resin on the roller. It's very thin & wets easily but don't try to roll or work it too much. I never go trying to mix epoxies & polyester materials they don't always stick to one another over time.