Yellowing

Topic: Yellowing (Read 1280 times) previous topic - next topic

Yellowing

July 10, 2011, 01:37:46 am

I'm afraid to ask but what would be the cause of yellowing in patches along the side of the coach? I see it along the seems and in various places. There doesn't seem to be anything different about these areas vs. the normal white adjacent. The fiberglass feels just fine but I'm suspecting that this has to be the result of something going on under the skin.

Re: Yellowing

Reply #1 – July 10, 2011, 11:47:13 am

Are you thinking about FBP? Some of us need a reason to go that route.

Re: Yellowing

Reply #2 – July 10, 2011, 11:53:11 am

My GUESS would be the jel coat is thinner where it appears yellowish, the fiber resin tends to be a yellowish shade I think. George is right, might be a good excuse for paint.
As usual FWIW

Re: Yellowing

Reply #3 – July 10, 2011, 01:25:22 pm

I'm not too concerned about looks but I am about integrity. Paint is so far out of my thinking right now I can't tell you. Up until now my major cosmetic problem has been the front vinyl stickers. I'd like to find a replacement set. It is ironic that I'm getting these yellow areas while my side vinyl still looks good.

Re: Yellowing

Reply #4 – July 10, 2011, 07:28:21 pm

Dwayne, not knowing exactly where or what shape the stain is its hard to tell. Fiberglass naturally yellows with UV exposure and time but the heavy load of pigment in the gel coat usually prevents yellowing on the surface. Most often, yellowing on gel coat is caused by someone using a solvent that reacts with the resin in the gel coat. If somone tried to clean the surface with the wrong product it could result in yellowing. Does the stain have a pattern that looks as though someone wiped something over the gel coat.

A second possibility, I hope this ins't the case, but its possible that rust may be occurring behind the fiberglass and the rust stain seeping to the surface. I don't recall whether the frame is steel or aluminum in the areas where the yellowing is occurring. If its aluminum then this isn't the answer. If the frame is steel and the yellowing correlates to the diamond shape frame under the fiberglass skin, you need to find how water is entering the coach skin.

Re: Yellowing

Reply #5 – July 10, 2011, 08:30:41 pm

It is on the left side above the compartments but below the vinyl graphics. There is an odd perfectly white square area just forward of the access door to the air filter of almost the size of the access door total absent of yellowing. The yellowing is in patches along the area above the compartments but below the graphics. I would have to say that it does appear as a bleed through. I don't know how water could be accessing just this area to create rust behind the fiberglass. I know the integrity of the areas in question feels very solid. This isn't happening on the other side. I'm really at a loss. I'm going to take a magnet and see if I can determine where there might be metal vs. aluminum. Where along the sides would one expect to find metal vs. aluminum?

Re: Yellowing

Reply #6 – July 10, 2011, 10:11:40 pm

Dwayne, I had one more thought. There may have been body damage some time in the past. If so the fiberglass patches had to be painted to match the rest of the coach. You can not gel coat a patch. The paint may be discoloring.

Re: Yellowing

Reply #7 – July 10, 2011, 10:55:05 pm

Quote from: Kent Speers – July 10, 2011, 10:11:40 pm

... You can not gel coat a patch. ...

Kent,

There was damage to the front of our coach long before we bought it. It was repaired and appears to have been finished with gel coat. Xtreme P&G recently repaired some damage to the rear. New gel coat was applied to some cracked and crazed areas extending from a damaged area. The actual broken pieces were low and were painted to match previous paint on the lower parts of the body.

I guess I don't understand why gel coat can't be applied over a patch. Can you expand your comment for the benefit of this slower learner?

Re: Yellowing

Reply #8 – July 11, 2011, 12:47:00 pm

Dwayne, I've tried to send you a pm but I don't think the messages made the trip. If you want, give me a call @ 870 556 0138. Will discuss yellowing.

Dub McBride

Re: Yellowing

Reply #9 – July 11, 2011, 04:00:22 pm

JD, I just got myself educated. I called James Stallings at Xtreme. They are one of the few shops that does apply gel coat by HVLP spray gun for repairs to gel coated fiberglass. I have never known of a body shop doing this so that goes to show that experts can be wrong. I consider myself an expert on resins and coatings maybe erroneously. James went on to say that the yellowing as it pertains to this thread could be the result of an incompatible gel coat resin or a bad mixture of the fillers pigments and resin. There have been many versions of gel coat resin over the years and repairing fiberglass with an incompatible resin or a gel coat that was not formulated like the original gel coat could cause the yellowing spots over time.

I have now learned something new about fiberglass repairs. Thanks to you and to James!

Re: Yellowing

Reply #10 – July 11, 2011, 04:30:04 pm

Kent,

Thanks for the reply.

I watched Rance spray gel coat onto my coach over an area that he had ground down previously. It looked like something that could be done over a patch or native fiberglass. He put it on thick and then ground/buffed/polished it to a beautiful finish.

Marilyn now asks if I can do something to make the rest of the gel coat look more like that area. Sigh!

Re: Yellowing

Reply #11 – July 11, 2011, 04:35:34 pm

FBP at Xtreme is in your future....may be distant future, but the coaches love for us to spend $$ on them...

Re: Yellowing

Reply #12 – July 11, 2011, 05:10:16 pm

Quote from: Jeff Savournin – July 11, 2011, 04:35:34 pm

FBP at Xtreme is in your future....may be distant future, but the coaches love for us to spend $$ on them...

Nope! We have seen some pretty coaches with FBP. However, our preferences for our coach run to the simpler graphics, and ... our current graphics are painted. Some buffing on the sides, and serious buffing on the roof will do nicely.

Also, our coach stays comfy with stock air conditioning even in the 100+F heat. The coach is in our driveway with no awnings deployed. The indoor temperature is fine with no modifications to the AC units or ductwork, and the 'fridge is working nicely. That mostly white exterior reflects a lot of heat.

We have had guests in, so we have been using the coach as the spare room.

Re: Yellowing

Reply #13 – July 11, 2011, 05:11:20 pm

Quote from: Jeff Savournin – July 11, 2011, 04:35:34 pm

FBP at Xtreme is in your future....may be distant future, but the coaches love for us to spend $$ on them...

You should know about that Jeffy. Nac loves you!!!

Re: Yellowing

Reply #14 – July 11, 2011, 05:17:43 pm

We are Nacs stimulous plan. American Express sure loves me. They call me often and ask about the charges.

Re: Yellowing

Reply #15 – July 11, 2011, 09:03:26 pm

I scratched a fraction of an inch to see that it is only on the surface. Here are two photos of the crazy patterns.

Re: Yellowing

Reply #16 – July 11, 2011, 09:18:59 pm

Dwayne, that really is crazy. I don't have any idea of what caused that but if it scrapes off you should be able to fix it. Try using rubbing compound but be careful not to remove too much finish. You may also need to user very fine sand paper to wet sand the yellow off. If it was mine I think I would take it to a local body shop and let them have a crack a removal. I hate sanding large areas if I don't have the proper equipment.

Re: Yellowing

Reply #17 – July 12, 2011, 08:40:04 am

Extreme paint mentioned trying a 3m product called Finesse.......... I plan to when the weather gets cooler, I have similar yellowing spots.

Re: Yellowing

Reply #18 – July 12, 2011, 03:21:08 pm

Rance at Xtreme buffed my coach with Aqua Buff.

Re: Yellowing

Reply #19 – July 12, 2011, 08:36:07 pm

I lightly wet sanded the area today. It looks better but uneven and now I'm thinking I shouldn't have done it. There was no way that was coming off without some of the finish. I guess I'm going to have to keep that side waxed up and hope for the best.

Re: Yellowing

Reply #20 – July 16, 2011, 07:27:35 pm

That is caused by bleed thru or bad gelcoat. Have a mobile touch up guy paint the area. Cheapest. Gelcoat can be sprayed. How does it get in a mold to begin with? Any good paint guy can spray gelcoat. Try wet sanding the end of a bay door that can't be seen. Doubt it will fix it however.

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