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Quick paint prep question

uk_figs

uk_figs

Well Known Member
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Prepping my -7 for paint this winter and going with the PPG Concept paint with K36 high build primer. I am using the raw epoxy approach for pinholes on the cowling prior to the primer application but wondered what I need to do on the gel coated wing an tail tip parts. Do I need to sand and epoxy coat and then prime or just sand and roll/shoot the K36 primer.:confused:
 
Clean thoroughly before sanding (and after). There is probably release wax on the gelcoat and sanding will just drive it in. Ask how I know.
 
System Three Clearcoat

I recommend a 12 oz kit of Sytem Three Clear Coat epoxy for pinhole filling.

It's epoxy, but is very thin and gets into the pinholes well. Designed as a moisture barrier coat for below the waterline on boats so it's tough enough for our purposes.

Available from a variety of sources; one source is Woodcraft (www.woodcraft.com) Item #144501

Good luck,
Mike
 
Dan H.

Dan has explained this process very carefully and in great detail. Check the archives with the search function. You probably have everything you need already......
 
K36

A really good primer. You might try the optional mix using paint. It covers very well and still builds and sands well.

Ken
 
K-36

Its pretty simple, sand with 180 on a DA, roll the K-36 on the cowl/fiberglass pieces, then squeege it back and forth filling the pinholes. Sand and repeat if nessessary, but usually one or two passes filss everything. bigger holes can be filled with glazing. I sand the gel-coated pieces with 180 on my DA to remove the cloth weave and shine, then spray with the K-36 a nice heavy coat. Come back and fill the pinholes with 2 part metal glaze. Sand down smooth and recoat. Usually 2 applicatins will create a flawless surface.
 
Purpose of tinted primer

What would be the purpose of the tinted primer approach, I assume mixing the topcoat color would change the color of both so is this to get the primer color closer to the finish color?
As I understand the PPG paint process from reading the archives I will be shooting a epoxy primer surfacer over the plane and then the topcoat, does the tinted K36 take the place of the primer surfacer (DPS 3051/55) for the fiberglass parts?
 
uk_figs said:
As I understand the PPG paint process from reading the archives I will be shooting a epoxy primer surfacer over the plane and then the topcoat, does the tinted K36 take the place of the primer surfacer (DPS 3051/55) for the fiberglass parts?
Click to expand...

DPS305x is an acrylic primer/surfacer, just like K36. In fact, the MSDS sheets suggest they are nearly identical products. The purpose of either is to build up thickness for block sanding. That's why they contain a lot of talc, barium sulfate, and titanium dioxide.

For polyester gelcoat, I'd fix defects with ordinary polyester putty, sand, shoot DPLF epoxy primer as a visual check and tie coat, immediately fix what I missed and spray K36 or DPS305x. After cure, block sand, reshoot and block again if necessary, shoot paint.

As for aluminum, below I've reprinted the word direct from PPG. I had a terrible time spraying DX1791, so I gave up and switched to a good scuff and wash followed by #6. However, I did not include the DPS305x. On one hand, spraying DPS after the epoxy prime coats would have allowed block sanding prior to the color coats. On the other hand, I thought it would leave the rivet heads looking half filled.

Thank you for your interest in PPG Refinish products. Aluminum may be refinished by one of the following Deltron combinations:

1. Etch primer DX1791, DPLF Epoxy, DBC, Deltron Clearcoat of choice
2. Etch primer DX1791, DPS3055, DAS3025, DBC, Deltron Clearcoat of choice
3. Etch primer DPX171, DPS3055, DAS3025, DBC, Deltron Clearcoat of choice
4. DX533, DX503, DPLF Epoxy, DBC, Deltron Clearcoat of choice
5. DX533, DX503, DPLF Epoxy, DPS3055, DAS3025, DBC, Deltron Clearcoat of choice
6. DPLF Epoxy(2 coats) DPS3055, DBC, Deltron Clearcoat of choice

These are just some of the combinations. All told there are probably another 10 more. A lot would depend on whether or not sanding is necessary (DPS3055, K36, K38 all require sanding...). The most common combination involves DPLF Epoxy somewhere in the mix. Options 1 and 4 are the most common. The rest is up to you.

A few things to keep in mind:
1. You CAN NOT apply DPLF Epoxy over DPX171 Etch primer. The only Etch products that may go under DPLF are the DX1791 Etch primer, and the DX503 Aluminum Conditioner.
2 If you decide to use the Metal Treatments (DX533 & DX503), you can not use any other kind of Etch primer as well (DX1791, DPX171)
3. DCC Concept Acrylic Urethane Single Stage may be used in place of DBC basecoat if you decide not to clearcoat.

If further assistance is required, please contact us at the Technical Service number listed below or visit our website at www.ppgrefinish.com.
 
Thanks for the feedback

Dan
The DPS3055 that you used is also what my local paint store guy recommended after a wash and scotchbrite, in reading the data sheet however it states that you need to shoot the topcoat within a week of application for a good bond.
I was planning to get all the fiberglass parts prepped, sanded and primed etc ready for final paint and then set up the paint booth later to start painting.If I prime and finish sand the parts now as you suggest will that cause a problem if I cannot paint the top coat for a while?
 
Dave,
I did not use any DPS3055. If I did, I would not shoot it on bare aluminum; see the list of recomended combinations from PPG Tech. If I shot anything for which the data sheet specifies a topcoat time window, I would follow those instructions to the letter.
 
correction

Dan
Your correct, the guy recommended DPLF on the scuffed aluminum followed by DPS3055 followed by the topcoat.
 
#$$#^%^$ pin holes

OK I think I have filled all the pin holes and after concentrating on the cowling I could not believe how many pin holes were in the wheel pants:mad:
I have sprayed a coat of K36 over the fiberglass parts and have a couple of questions:
1. In reviewing the archives I noticed a post that mentioned to use DPLF epoxy primer as the tie coat and then the K36, I was under the impression that the DPLF was for the scuffed aluminum, did I miss a step on the fiberglass:confused:
2. How many coats of K36 do I need to shoot (and wet sand) on the fiberglass parts before the top coat and how good does the finish have to be before the top coat is applied.
 
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