Jump to content

exterior fiberglass gel coat hole repair ideas


Recommended Posts

I managed to make a few holes in the white exterior fiberglass on my '87 Sunrader.  Small, maybe 1/16" to 1/8" across.  Basically looks like a screw hole that needs to be filled.  There are a lot of gel coat white repair options out there but I was wondering if anyone has had any specific experience with a product that has produced a good result.   

This item looks like would work well (shower/tub repair):

https://www.amazon.com/gp/product/B00KO6LTO6/

The Marine Tex  is also popular:

https://www.amazon.com/gp/product/B0014419V0/

Both request a constant temp of 55 to 60 F to do the repair process so I'm not doing this any time soon so I thought I'd get some input here while I wait for the weather to warm up....

Link to comment
Share on other sites

Six tiny holes about 8 inches apart in a 3 square foot area.  A picture of one of them is attached.  The chipped area on that one is about ~3/16" across  Stupidly, I was using a nail gun to attach some interior trim and the nails were just a wee bit too long and poked the holes from the inside to the outside.  I'll dremmel them  out on the outside to make a ~1/4" cone with clean edges and then fill and sand.  I'll strip the wax first, sand and polish and then re-wax.  More than likely the repairs will be more white than the surrounding area but I'm not sure if it's worth the trouble to try and color match.  

 

IMG_20190201_173033386.jpg

Link to comment
Share on other sites

sounds like you have a plan. after your repair, possibly you could cover over the unsightly area with an interesting vinyl graphic of some sort , to prevent trying to match the paint, a cosmetic band aid approach. just my thoughts. wish you well. joe from dover.

Link to comment
Share on other sites

You could use Bondo but the marine tex will work fine. Fake off the pieces first then fill and sand. Treat it like an auto body repair. Finish with ery fine wet grade sandpaper. When your done this paint is a very close Sunrader match. Just feather the edges so it will blend

https://www.brandsport.com/dupl-bfm0041.html?gclid=Cj0KCQiA-c_iBRChARIsAGCOpB37szWj9u-YQehWcdh73tUzweHsHUBsgKI0v-_MPmBR4IhlIcCGESIaAm8AEALw_wcB

This color is available tons of places. Many auto parts stores have it so no online ordering needed

Linda S

Link to comment
Share on other sites

Thanks for the info Linda S.  I'll get the Marine Tex and see how it turns out.  I've got a good set of wet sanding supplies so I should be able to get a nice smooth finish.  If it looks good enough after that I'll leave it as-is.  But if not then I'll use your suggestion and get that paint.  

In terms of matching color I had not thought about actually using paint to cover the (presumably) bright white gel coat repair material to make it blend into the more weathered surrounding gel coat.  Brilliant!  It's too expensive and tedious to buy and mix colors to make the Marine Tex material the right color but that would be a way to do it without paint.    I've got some experience with auto paint chip repair so this would be a pretty easy final step if I want to make it blend better.  Sure would be nice to not be reminded of my dumb mistake with the finishing gun every time I see those six bright white dots on the side of the camper...

Link to comment
Share on other sites

Unfortunately, you've not only got to colour match, but also texture and gloss match unless you start wet sanding the whole house.

Could you use one of these to hide the repair? I don't know if they're available larger than 11"x17".

71Blks0HOIL._SY355_.jpg

https://www.amazon.com/State-Sticker-Travel-Map-Accessories/dp/B01DV8EORC

EDIT: You might have to add Canada to your travel plans to cover everything. :)

State-Stickers-Decal-Map-Kit-for-the-RV-

 

Link to comment
Share on other sites

Well we don't usually sand Sunraders we polish them with Barkeepers friend and then Zep wax them. If the paint is too glossy though all you need to do is use your fine wet sand paper but use it dry and go over the painted area with a light touch. Weathering paint is easy. Perfect glossy finishes are hard.

Linda S

Link to comment
Share on other sites

I use the "Barkeepers friend and then Zep wax" process that Linda S mentioned.  It's worked well for me for the last 4 years I've had this '87 Sunrader.    Stripper takes it back down to the chalky white dull gel coat finish.  As Linda S mentions it should not be hard to match the finish when stripped.   Then the Zep  wax across the whole area will give it the same general gloss level.  I'm not super picky about how it looks overall.  I'll even skip the paint if the patch looks good enough (I did find the paint down the street for $8 if I need it).  The patch kit will be here Monday or Tuesday and I'll post of pic of how it turns out.   

FYI, I recently used the Zep stripper to re-do the rear on the camper.  It really takes that wax off quickly and easily.  I had put it on too thick and it's facing the sun when parked and it got a bit yellow.  I did ~4 lighter coats and it came out much better.  I have not had to re-do the rest of the camper (except the roof once) with the Zep in 4 years.  I just clean it really well once a year and then put another thin coat of wax on top.  It's no stunner but it looks fine.

I do like your map stickers Derek, although I've only done a few states in the South East so mine would look pretty sparse if I went that route!  I'm actually experimenting with taking all of the old vinyl decals off the outside because I'm aiming for an overall 'naked' decal/sticker-less look; however, the ghost image of the old decals from weathering may keep me from doing that.  

Link to comment
Share on other sites

I'm posting some pictures so that someone else who needs to fill a screw hole can see what I ended up with after the Marine Tex.

I stripped the wax with the Zep stripper, scrubbed with Barkeeper's Friend, cleaned with acetone, used a rotary grinder bit to go from rough hole to smooth edged hole (as shown in two pics).  I wet sanded with 1000 grit to get it all smooth and flat.  I cleaned in acetone again and applied a small amount of the Marine Tex repair, smoothed over with a razor as shown in third pic.  I kept the level of the epoxy just below the surface as I plan to fill flat with several layers of paint and then feather the paint with wet sanding into the surrounding gel coat.   Linda S was correct that Bondo would have been a perfectly suitable substitute for the Marine Tex.  If I had tinted the Marine Tex (a rather difficult task when starting with the primary colors that come in a tinting kit) then i could have made a nice resin matching patch that would be more structurally similar to the fiberglass, but I just don't think structural integrity matters with a small hole like this.  

The color of the repair is really bright white and makes the 1/4" diameter divot stick out really bad.  So I have purchased the can of the Duplicolor paint and testing indicates that it is a good match - way way better than the polar white of the repair!  It's going to take a day or two for the Marine Tex to dry enough to paint and wet sand so I'll post some pics of the finished job later in the week.

Derek, In thinking about it I actually I think I could list a lot more states on the map without cheating.  It's been with me for only 4 years but it has been in the family (parents/brothers) since '94 and has been across the country from coast to coast twice in that time.  Certainly that amount of travel could cover some blemishes!

IMG_20190204_133120365.jpg

IMG_20190204_124442397.jpg

IMG_20190204_123001717.jpg

Link to comment
Share on other sites

Well, color matching was harder than I thought it would be.  The Wimbledon White was pretty yellow out of the can (first image), so I bought a second can of "competition white" (also a generic Ford color, but sort of off-white).  I mixed the two paints to try and get a match but the second photo is as good as I could do.  I had to add some black to knock it back.  Final result is the third image.  You can still see the spots, but it's acceptable.  One could do better with effort and better tinting supplies.  You don't notice the holes now unless you already know they are there.  Good enough.   

I think the best approach to this kind of project is to try an avoid putting holes into the fiberglass gel coat!   The off the shelf duplicolor paint isn't going to be an exact match - and everybody's color will be different due to weathering.  Heck, the color of my panel varied quite a bit just in the area of the holes I was patching.  Color mixing the paint (or you could color mix epoxy) is the only way I could find to actually make the repair non-obvious.  Of course one can always fall back to the map decals to hide a repair!

 

IMG_20190205_114625616.jpg

IMG_20190205_124404836.jpg

IMG_20190205_153526921.jpg

Link to comment
Share on other sites

Yea, it would be possible to get a custom paint color, but for this job that amount of time and effort exceeded my available gumption at the moment.  If I ever need to do a more major repair I'd likely go that route.  Since I used a flash in the pictures, the actual match looks a little better than the photo suggests in regular outdoor light.  Good enough to cover my blunder.

Link to comment
Share on other sites

Just a quick follow up for anyone reading this in the future who is planning to do a fiberglass fix.  If I were starting over I'd buy the Marine Tex kit (~$15) and some powdered mica colors to tint the epoxy.  The tints can be found in the range of $10 to $15 at Amazon or Ebay.  Overall that would be a better process because it's one material to spread and sand.  The gel coat is pretty thick and by putting the epoxy on a little thick and spreading out about 1/8" past the edge of the repair area one could sand down reasonably flat and blend epoxy and original material without risk of going through the gel coat.  It would be easier than getting the paint to layer thick enough to sand.  It would be easier to match color with the tint set too.  I've done this approach with a vinyl patch kit and it really is possible to get an 'exact' match this way.

BTW, I put the Zep wax on today and it looks good.  from a few feet away you have to know what you are looking for to be able to distinguish the patches.  I'm happy with the overall repair.

Link to comment
Share on other sites

  • 3 years later...

I'm posting an update to this old thread in order to give some follow up info and an application idea for using the Marine Tex to repair gel coat.

I'm using the Marine Tex White plus powdered mica pigments to make it match the gel coat color:

Marine Tex: https://www.amazon.com/gp/product/B0014419V0

Mica Pigment set: https://www.amazon.com/gp/product/B08HJX1ZHB

 

I used a 50:50 mix of the 'golden' and 'yellow' mica powders from the $6 kit above and added it to the Marine Tex (before hardener) to get a good color match.  It will dry a little darker than when wet.  

The key thing I want to share here is a handy application method that really made it easier to get a nice smooth application with good feathering into the original surface with very little sanding required after drying.  The Marine Tex is rather sticky and it can be difficult to get a nice smooth even surface - and this can require a lot of careful sanding after drying. It's easy to cut through the gel coat and mess it up when trying to sand down a Marine Tex patch repair.  But what I found is that if I use isopropyl alcohol (70% fine, 90% better if you can find it) as a lubricant then I can very easily smooth out and shape the Marine Tex before it dries.  I use a purple nitrile glove and either wet a finger or drop the alcohol onto the surface and then rub it to get the Marine Tex shaped and smoothed the way I want.  Don't use too much or it will start to absorb into the Marine Tex - just enough to make the top surface pliable and smooth.  Add a little  more alcohol if it dries out while working.

 

I use the Zep wax and I strip the area I'm working on down to the gel coat to do the patch and then apply the zep wax over the finished patch.

I've done small chip and hole repairs this way and I can hardly see the repair in most cases.  I even did a large 6" diameter patch on the roof where I removed a bathroom fan.  (I wedged a wood circle up as a backer and put 2 layers of fiberglass down and then Marine Tex over the top in a thin (~1/16") layer.  It's been holding up just fine.)  

In one particular 2 square foot area I had some "flaking" of the gel coat where it was lifting off or delaminating from the fiberglass in small flakes with raised edges.  not sure what caused it but I was able to make a good repair over this area by applying a carefully color matched batch of Marine Tex and then aggressively rubbing it into the flakes to fill (again using the isoproply alcohol trick) and then I was able to feather the remaining Marine Tex out to a nice thin well blended layer with excellent color match.  Even as a very thin layer it bonded well to the clean (roughened) gel coat.  Once dry and re waxed with the Zep it looks quite good - vastly better than the chipping gelcoat that was there before.  It's been about a month and all of the repairs using the isopropyl alcohol method are holding up great with no noticeable impact of the alcohol on the dried Marine Tex.

Link to comment
Share on other sites

this is cool; will need to revisit my bumper sticker hack job covering where I punched through my shell accidentally while drunkenly pushing a two place sled trailer a bit too hard. The hole is about 1.5 inches long by 1 inch...

-currently covered by a yellowstone park bumper sticker

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...