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I made an aluminum backing plate for my transom. To make it a little more rigid I had an aluminum "I" beam welded on the plate. My transom has a slight bow (wood is in good shape) so we clamped/bolted the pieces together so the reinforcement plate fit snug and tight . We covered the area with leather but the spray of the MIG welder when tacking in place, managed to find areas of gel coat with tiny little burn pockets from the welding spray. Not all the way through and looks like "acne". Suggestions for repair appreciated. I have never sprayed gel coat but I have some left over from other work done on the hull earlier this summer. I also repaired/filled some holes in the transom from electronic wires. I was planning on brushing on the gel coat in those area but the "pimpling" would be a month of Sundays this method. Not an area of the boat that I care about the aesthetics. Thanks.

Garris

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gchuba - If you plan to spray it, it's really not very hard. Its just time consuming, especially the work involved with mechanically surfacing (wet sanding, buffing, waxing). Also, if your boat is somewhat old the color match may not be perfect even if you purchase factor-matched gel coat - but it sounds like that isn't critical to you. I sprayed the central exterior transom of my Sport 15 this past fall - came out beautiful. I used a Preval sprayer which worked out great: http://www.whalercentral.com/userphot...lbum_id=64

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wlagarde, thank you for the reply. I will plan on using the Preval sprayer. How much gel coat do you think I should use for the splash well (how high up in the bottle?). I saw it is a 9 oz. bottle. I will be tilting it down to get to the bottom of the splash well. I can use remnants of the mix for the spot repair on the outside of the transom. How long is the batch good for once the hardener added? Does the over spray look odd if I tackle old screw holes on the hull for spot repair? Would hole repair best be done with a brush? Thanks.

Garris

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I'd be surprised if you used more than 2 oz.
The Gel coat I worked with from Tap Plastics was only good to work with for about 10 minutes.
You might have to try 1 hole to see how the over-spray looks. May be easiest to fill screw holes by tapering hole 1st with drill bit, then using brush.

Doug

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Doug, the backing of the holes are filled with Splash Zone. Slightly below finished surface with the edges ever so slightly tapered. A dash of SB-112 epoxy to help the adherence. I guess I will shoot the interior of the transom and fool with a hole or two. I do not know if the spraying leaves a distinctive over spray "splash" that would leave me with more sanding than just a brushed on spot repair.

Garris

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Garris, from what I've watched on Youtube instructional videos, they usually tape a larger area and you do have to feather the edge of the sprayed area. If you didn't tape, I think you would have a quick sanding, but probably more work than brushing each one separately. Let us know what you find works best.

Thanks,
Doug

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Garris - Fill any screw holes etc located within the transom well with patch paste and let harden. Then sand smooth. Mask the area you want to cover and then spray 2 successive coats without surfacing wax. Add surfacing wax to the 3rd coat. You have about 10-15min before the gel coat hardens for each coat (the more hardener the less time, the less hardener the more time, etc). Once the final coat has hardened for 24-48hrs start wet sanding as described on my project page. Alternatively you can mask a larger area and then feather the edges. If the gelcoat match is good you can skip feathering. Also when spraying the area in my project page I filled the entire canister on the preval sprayer and almost emptied it for each coat. If your area is smaller you can use proportionately less. The idea is to build up enough thickness so you have enough material to work with as you sand it down smooth and then buff/wax.

For screw holes located elsewhere on the hull I would consider using color matched patch paste. Use masking tape to mask a small circular area around each hole. Fill with patch past using a putty knife, cover with wax paper, and let cure. Remove the masking tape/wax paper and then sand with wet sand paper gradating upward from 220 to 400, to 800, to 1000, then buffing compound, and then wax.

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Fellows, there are already a lot of screw holes and poorly matched repairs on this hull. The majority of the transom will be hidden by my aluminum backing plate. I am looking for a structural half decent aesthetic overlay for this particular area. If three coats are necessary, so be it. I want to do it structurally correct.

Does anyone know if one coat of gel coat with the wax hardener is an OK repair even if it leaves shadows underneath. If one spraying leaves too thin a layer, I will junk the idea and go with three. I am just going with a brush dabbed in the gel coat for the screw holes.

I just did a layer of the Splash Zone and really studied the dimples and heat damaged areas from the tack welds. I removed the discolored gel coating from the heated areas and got down to good material underneath. Only a couple of spots where the gel coat had to be completely removed. Mostly a surface annoyance leaving spots compromised, not ruined. I am impressed with just how tough the gel coat is.

I am toying with the idea that wherever the Splash Zone is, to brush a layer of gel coat. Sand the spots smooth and then shoot the transom. One or three coats depending on the consensus. Individual hole repairs at other parts of the boat. Fill the holes with the Zone, leaving them a little shy, dab them with gel coat, sand. I am looking at my own scars and only want the boat healed.

Garris

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If structural issues are all you are worried about I would use patch paste to fill the holes. You could try brushing also which should work if the holes aren't too deep. As for spraying one coat won't do it. Gel coat does not self-level like Awl-grip or spray paint does so the surface will be rough. The reason 3 coats are needed is to allow for you to mechanically smooth the surface without sanding through the material you deposited with the spray gun. Good luck with your repair and let us know how it turns out!

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I think when I was watching a spray application, they had a roller to measure thickness. They were targeting .020"

Just got my 1st boat about 6 weeks ago. Was really babying it until I starting repairing some Gel Coat areas on the hull. That fiberglass/Gel Coat structure is really tough.

If I am not mistaken, you'll need to cover the large spray area with PVA that can also be sprayed with the same type sprayer. It's a water soluable plastic film so the Gel Coat cures. Let the Gel Coat set up a little, then apply the PVA. (Poly Vinyl Alcohol). Smaller areas can be covered with PVA, Seran Wrap or Mylar sheet stock. I really found the PVA the easiest to work with.

Doug

Doug

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wlagarde, thanks. You answered what I needed to know. I am not after perfect but I do want to make the splatter holes level. I will do the three coats. I thought if I went a little heavy the gel coat would fill in with one spray. This is my transom and once I mount the plate I do not plan on going back in there.

dougt, I am adding the wax hardener so no need for the PVA

A related issue. I have bottom paint and filled in my transom drain that was submerged. I have the ablative paint but I was wondering if I could use my epoxy resin (West System or SB-112) as an underlay to the bottom paint and overlay the gel coat repair. Just the one drain (6" rounded area) plus a couple of transducer mount areas. Do I just paint over the area or do I need to get a product for sealing the transom before painting. Thanks.

Garris

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GC,

One thing to consider is that most f\g resin and gelcoats don't play well with epoxy resin. Maybe some of the newer products do but the older stuff was either or.

Good luck with the project

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tothemax, thanks for the contribution. Finnegan earlier mentioned the incapability of of gel coat over epoxy resin. Some fellows mentioned that the amine "blush" was the issue (can be cleansed). Also, it is a mechanical adhesion. I am utilizing bits and pieces from everyone. I like the Splash Zone (resin base) as my repair coming to the surface with wooden plugs filling the larger voids. I am leaving the Zone a little shallow as well as rough. I am also using the SB-112 as a primer before gel coating. It is described as a bonding agent for an overlay of gel coat over a resin. May be overkill but have it on the shelf. My first time with this attempt. Just purchased three Preval sprayers (whole sprayer is only one dollar more than the replacement cartridge and do not want to deal with cleaning a one dollar bottle). I am a hack with sealants and generally get runs in spraying. Will give it my best effort. My motor and jack late are off and am going to tackle the areas readily accessible. I have a week before type III anodizing is done on my aluminum so going to do my best with prep and installation to get acquainted with materials for other parts of boat that matter more. Thanks all so far and keep the comments coming.

Garris

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Sounds good Garris, keep us posted on your learning's.

Best regards,
Doug

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Well, I finally had the correct conditions (work and weather)to continue with the gel coat. I mismatched the color for my initial overlay and my prep for redoing the overlay was a blessing in disguise. Two observations of note.

One. There was a tiny area of my repair where I missed SB 112 "primer" over a spot that was repaired by Splash Zone. I brushed on my gel coat anyway. When I sanded for prep of my new overlay coat it was the only area that flaked. The outer shell looked identical to all the other repairs but it "chipped" at this one spot. I did have a rough sanded finish and an acetone cleansing over the entire work area beforehand so my first coat of brushed on gel coat could fill voids before spraying. None of the other areas with the SB 112 flaked or chipped.

Two. As I sanded the areas for my new brushed application of gel coat I found that my sloppiness of the SB 112 created a lot more work. I over applied the primer thinking that it would aid in blending. All it did was create an irregular surface that left more sanding. The SB 112 has a specific time window to work with and once you miss it, you need to remove it. My sanding brought up some of my splash zone to the surface (I was fairly aggressive with the sanding for color removal of my mismatched gel coat). I am now going to daub it on the specific areas with a small brush (flux brush for copper soldering) keeping as clean as possible.

Other than these bumps in the road, the repair is acting/proceeding like I thought it would. I am purchasing a die grinder to chase some of the spider web cracks for additional repair while all is exposed. Also some additional tubing for brass drain replacement while all opened up. "Replacing the faucet washer" is slowly becoming a kitchen. I am so glad I am emotionally resolved to miss the boating season this year.

Garris

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Miss boating season? That is why so many here have more than one I suspect. I have a major delamination on my 1964 16 but it simply means that the 1966 will finally start to get some use.

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mtown, I owe quite a few fishing trips for next year. There is still a local salmon bite going on.

Garris