Something went wrong with my fiberglassing

[H3newdog]

I have a 1983 H34 that has (had) cracks in the port and starboard tabbing between the liner and the hull. After a lot of research on how to repair the fiberglass I thought I'd done a good job. Noticed a few bubbles that I cut out. Then I decided to clean up the edges with a chisel. This is where the problem came up. As I poked and lifted the excess more and more of the new work started to lift off. I cut a few pieces off and looked at the underside, they were smooth, very smooth underneath (pic 3). Whatever adhesion was holding the new glass in place is giving it up with only a little prying with a short 1" wood chisel. Maybe someone can tell me what I did wrong.

1. Used vibrating saw to cut out broken material.
2. Wipe entire area with acetone.
3. Used grinder with coarse sanding disc ,wire wheels, wire cups and random orbit sander with 80 grit. Feathered everything I could so there wer e no sharp edges. Removed most of the "white top coat on the liner as I didn't know if it was strong enough. Note that when I removed the separated pieces they only had spotty adhesion on some of the white areas.
4. Wiped down several times with acetone then more grinding. I used the wood chisel to test/find then help remove the loose material.
5. Wiped with bottom prep de-waxer D95.
ready for glassing
6. Mixed West system 105 & 206. Used paint brush to wet the surface then laid dry 7oz mat in place then used paint brush to saturate mat. I laid the mats with excess which I planned to trim off later.
7. About an hour latter mixed more 105 & 205 added 28oz mat and saturated. Used small roller to push out air bubbles. Everything looked real good when I left and when I came back two days later.



I took a long time researching this fix even had a few other owners in the yard look at it so I wouldn't botch the job and have to do it again. Well now that I have done it once I'm better prepared to do it again with the exception of doing it right. Any help would be much appreciated.

 

[Ralph Johnstone]

5. Wiped with bottom prep de-waxer D95.

This is the only thing that 'may" have introduced some form of contamination seeing it was the last thing to be wiped on the FG before the epoxy was applied. Any chance the de-waxer accidentally may have received some form of contaminant in it ? ? ?

Couple of years ago I was doing some epoxy work (System Three) in the anchor locker and unbeknownst to me, dripped a large drop of epoxy on some recently waxed and bloody shiny gel coat on the deck. When I did see the drop some days later, tried to chip off the epoxy and it took a good sized piece of the gel coat with it when it came off. The point here is that epoxy seems to stick like sh!t to a blanket under the worst possible conditions (where you don't want it to). Hence my suspicion of the possibly contaminated de-waxer.

All I can suggest is to again prep the area for a new epoxy cloth application, but this time, test out several (many ?) small areas for adhesion of the epoxy to the FG substrate to be sure. Maybe skip the de-waxer this time as you've mechanically removed the FG surface plus acetone is a pretty good cleaner.

 

[H3newdog]

Hey Ralph, I'm following MS advise to use the de-waxer. I'm even using the same one he shows in tutorial. New can to boot. I'm with you on stuff that sticks more to you than what you want it to stick to. I didn't even think about trying a test area, That sounds like a really good idea as I don't want to go through the entire job a third time. Thanks.

 

[Apex]

think about the wiping utensil also, clean rag changed frequently.

 

[njlarry]

Give west system a call. Those guys know their stuff and are very helpful on the phone. The calls are even answered by real people!
Let us know their answer. Looks like you did everything right.

 

[H3newdog]

Apex, used paper towels, folded into squares, each side only once.

 

[ddrewry]

I have a similar problem using West epoxy. I called them yesterday and they were very helpful and as mentioned I was speaking to a real person. I have lots of experience with polyester resins but have only used epoxies in very small applications before this. I assumed the procedures and alternating matt and roving would be the same but I have areas that clearly were not wetting out like I'm used to now matter how much epoxy I used or how hard I tried to get the stuff in there. Couple of things from the West experts: 1st they said they generally don't use stranded matt fabric, said the material used to hold it together dissolves in epoxy resins. He also said they don't recommend woven roving and instead use a bidirectional stitched fabric. I am disappointed as everything I read said epoxy was better for repairs but the first results were not good...

I'll be grinding and sanding in the next few days and will try again with the new knowledge...but if it doesn't work, I'm moving back to polyester! will advise

 

[Alan Gomes]

I have a similar problem using West epoxy. I called them yesterday and they were very helpful and as mentioned I was speaking to a real person. I have lots of experience with polyester resins but have only used epoxies in very small applications before this. I assumed the procedures and alternating matt and roving would be the same but I have areas that clearly were not wetting out like I'm used to now matter how much epoxy I used or how hard I tried to get the stuff in there. Couple of things from the West experts: 1st they said they generally don't use stranded matt fabric, said the material used to hold it together dissolves in epoxy resins. He also said they don't recommend woven roving and instead use a bidirectional stitched fabric. I am disappointed as everything I read said epoxy was better for repairs but the first results were not good...

I'll be grinding and sanding in the next few days and will try again with the new knowledge...but if it doesn't work, I'm moving back to polyester! will advise

Perhaps you should consider vinylester resin as an alternative. Much better than polyester for secondary bonds but wets out like polyester.

 

[H3newdog]

Update. After showing others how easy the new glass came off along with how smooth the underside was I decided to get some pro advice from the glass-man of the boatyard. First he said that I used what he called "finishing" mat (very fine & leaves a smooth surface). That explains the very smooth surface underneath. Next he said to use the bi-axial cloth which the yard had and he cut me enough for three layers on each side.
He also recommended that I remove all the original tabbing as it was clearly applied over gelcoat on the liner. I had left the "non-cracked" original tabbing in place simply to save some work (if it's not crack/broke don't replace it).
The only good part about re-doing my glass job was that it came away very easily. Of course by now I had the tools and technique down to get it all cleaned up.

Pic's 1 & 5 are of the port side while 2, 3, 4 are starboard side where two seacocks mount.
Pic 1 shows how I used a vibe-saw & chisel to remove small pieces.
Pic 5 is after clearing & roughing but before wiping down with acetone.
Pic 2 shows the original ?? non-cracked tabbing I removed. This was consistent with what I removed all the way around. The removed piece is upside down just below the white area, gelcoat?, that I was told should not have been part of the connection. I noticed that it only stuck in a few spots. Also there are soft fibers in all the connections that I removed. My understanding is that soft indicates they were never saturated with resin.
Pic 3 shows how easy it was to remove original ?? with chisel.
Pic 4 is with all the original removed and ready for another round with the grinder.

Side Note: When I got the invoice from the yard for the bi-axle cloth I knew there was a mistake, 50" x 128"
for $12.00. I suggested there may be an error. They were very appreciative of me pointing the mistake and emailed me a corrected invoice, $19.00!!!!! That's a small percentage of what I spent on the smaller pieces of cloth. Who knew the best cloth at the best price was within walking distance!

 

[ddrewry]

update also...
I did lots of grinding to remove areas where the epoxy had not wetted the cloth properly and went back with the stitched biaxel cloth West recommended and everything went smooth. I tackle the larger areas in the next few days and see how that goes but so far it looks like my error for using matt and roving in an epoxy layup.

 

[thinwater]

update also...
I did lots of grinding to remove areas where the epoxy had not wetted the cloth properly and went back with the stitched biaxel cloth West recommended and everything went smooth. I tackle the larger areas in the next few days and see how that goes but so far it looks like my error for using matt and roving in an epoxy layup.

Mat has a binder that is not compatible with epoxy (it is dissolved by polyester resin but not by epoxy, and thus does not conform or bond well). This is the perhaps the primary reason biax is used with epoxy instead of mat/roving. A detail easily missed in your research. If you want a smooth surface use very light cloth for the last layer.

Also you de-wax BEFORE sanding, not after. The sanding will only push the contamination farther in. After sanding only light dust removal is needed.

Also scrub with TSP. If the last effort left any blush behind, solvent won't remove that.



http://www.westsystem.com/ss/surface-preparation/

 

[ddrewry]

Thanks! I'll check out the link as well. I am replacing the whole nose section so most of my layup is inside the hull. Not sure what TSP is but I'll find out. Thanks again!

 

[SFS]

TSP is trisodium phosphate, a stronger cleaner that comes in powder form. It is available in the paint section of big box stores and hardware stores.

http://www.homedepot.com/p/SAVOGRAN-1-lb-Box-TSP-Heavy-Duty-Cleaner-10621/202935861

 

[H3newdog]

I'm not sure what the difference is between Mat, cloth, roving etc. for fiberglass. I've not seen anything about not using a particular one with epoxy either.
So far so good with the bi-axle cloth. Had some difficulty with getting the side to flatten out. When I dry laid it it was fine but after wetting it out and rolling all the air bubbles out the parts that came up expanded somehow and would not lay flat. Anyone had this problem before? Any ideas to prevent in the future?
As for applying epoxy over epoxy West system instructions say : To remove the blush, wash the surface with clean water (not solvent) and an abrasive pad, such as Scotch-brite(TM) 7447 General Purpose Hand Pads.

 

[thinwater]

The trick where you need to bend the cloth is to make certain you are on the bias, not bending the fiber bundles directly. Sometimes a layer or 2 of lighter materials to start can help. Where I needed a smother finish I finished with one layer of 6 oz. cloth.

(I decided to make the boat longer. I installed the forms and laid up both extensions before lunch. Finishing took another 1.5 days, on-and-off. But this was not my first project. It takes practice.)

 

[H3newdog]

bend the cloth is to make certain you are on the bias

Could you explain this further. I see the weave but not sure what the bias you're referring to.
Sweet thinwater, I wish I had steps and a swim platform as I like to be in the water as much as possible.

 

[thinwater]

^^ The bundles should not cross a bend at a right angle. They should be at a 45 degree angle. That way the glass does not need to bend as sharply. If you look closely you can see that I laid them on the bias. It can also helps to loosen up the weave a little by massaging it. But it is also vital to eliminate any sharp corners by radiusing either with filets (inside) or grinding (outside). Anything lass than ~ 1" radius is tough for heavy biax; it will pop-up after wetting and the bond may be poor. 6 oz. is generally good for 1/2" radius. Mat has similar rules, but it only relaxes properly with polyester resin.

 

[H3newdog]

Thanks thinwater, that helps a lot.