"another transom job" Hints for next time

[alarie]

I just scanned the "transom job" post below and had a few thoughts on how it might have gone better:

1. Grind before you cut! It is much easier to mark out your cuts and grind all areas (for re-assembly) while they are in one piece. This will give you even and flat areas to glass onto when the time comes. Grind carefully and make it as flat as possible. Plan all before you begin with the heavy artillery and it will go better later on. Grind it all at once so you can be efficient when you go to glass (plus only one clean up). (On my 20' project I was grinding for about 4 days before I did the next step.)

2. Decide how much glass (layers) and make sure your grind area will allow this to fit without ridges at the edges.

3. Taper your glass at the edges so you do not have to remove excessive amounts when dry. This should fit nicely with the natural taper you get at the edges from a grinding disc.

4. Neatness counts! Be accurate with what you add back. Use clear plastic to pattern your glass. Tape it on, mark it out, and place over the glass to cut. Make each layer a bit smaller so you end up with a smooth edge. Put the biggest layer on first.

5. Use peel ply/release fabric, which will help you get the glass flat, air free, and even. You can hold onto the peel ply while you roll out the glass to push excess resin out and to make it even at the edges.

6. Fair with 36 grit on a DA sander once dry. Hold it flat and knock down any high spots/edges. Get it smooth before adding any fairing. The peel ply will give texture to any lows, so you can fair right over without sanding these low spots. Don't skimp here, as it is harder to fair with fairing than a 36 grit sander.

7. Get the air out of your fairing before you put it on. Put some of your putty on a piece of cardboard and "pull" it many times into a thin layer until the air bubbles are removed and it looks smooth. If you cannot do this, it is probably a little too thick. Once 90% of the bubbles are popped, put the fairing on. This will eliminate most of the holes that open up on sanding and get you to the end faster. ALWAYS DO THIS WHEN ADDING FAIRING OR YOU WILL HAVE BUBBLES, ESPECIALLY WHEN YOU SAND.

8. Add fairing in steps. With epoxy, make a "tight" trowel over the lows with a hard, stiff fairing knife (drywall tools are good). Do not put on excess, just fill back to your orginal surface. Once this has begun to cure (firm to the touch but you can still put your fingernail into it), add more right over the original, again no excess, just fill in any ridges and air holes. Keep going like this until you are satisfied you have enough on.

9. Sand with 60 grit or coarser. Use a HARD block if you really want it flat (or a DA if not so cosmic), not even those rubber ones. We use wood or aluminum. Add more fairing as above if necessary, but mix your stuff thinner as you get closer to fair. You should not have to do more than one additional fairing step, or you did not sand well enough before you added fairing.

10. If you are going to gelcoat, do it over 60 grit. Anything finer is a waste of time. The gel will fill in any sanding scratches, no problem.

11. AWLGRIP
-This is how the pro painters down the street told us to prep new surfaces (or old gelcoat for that matter), and is the method we use with great success. Believe me this is the fastest way to finish paint! These guys spray boats and masts every day for 25 years!
-sand all with 60 grit and do your best to fill any holes with fairing. Don't stress too much at this stage, just get it close.
-at some point when you think you are close Prime it with 545. They spray 4 coats typically. Use the gray, not the white, regardless of what you topcoat will be. The white does not cover well.
-Fill any pin holes/lows once the primer is cured, but before you sand!!!, but WITHIN 12-18 hours, otherwise you have to sand it all before you fill. With the surface one color, you can really see what is necessary. Use thin filler, and do not leave excess on the surface. Tedious process to fill all airholes, but faster than any other method. Use good light and get them all now.
-Sand with 100-120 grit. Dont worry about burn throughs, just sand it all until dull.
-Prime again as above. Fill any remaining pin holes as above. Less critical on non-skid areas, but very important on gloss.
-Sand 320 grit on a soft pad. Do not burn through! Spot prime any burn throughs.
-topcoat.

Hope this helps!
Peter

[warthog5]

A few exception's I will add.
The use of 545 Gray is fine, unless your going to paint it White. Then the 545 White primer is better.

Stop mixing your own fairing compound! the stirring of mixed epoxy add's air to it. Then adding a mix of microballon's & cabisol to keep it from slumping add's even more.
Use System 3's Quik Fair. Not only do they package this stuff under vacuum, but it set's up for sanding in aprox 7hrs. They say 4hrs, but I've found at 4hrs it still gunk's up your sandpaper.
Hamilton Marine is the chepest place to get it.

When I do a all over paint to the hull, they step's go like this.
1] Wash the hull with a dishwashing liquid in water to help cut the grease and oil.
2] Wash the whole hull down with wax&grease remover using the 2 towel method. Wipe it on wet and dry it with the other towel before it evparates.
3] Using a pencil, go over the hull with a fine tooth comb.[2 people are better] circle all the blem's.
If you find the hull extra wavy in a area spray a guide coat in that area and block the gellcoat.



You can see the high spot's showing here.



4] With pencil in hand, sand the hull with 80gt. Sanding in small area's at a time. Re pencil the blem's as you go and keep the DA FLAT!

5] Fill all the blem's with Quick Fair. On very small spot's use a single edge razor blade as a spreader.





6] Block sand all the fairing. Don't sand it with a DA sander if you want your boat stright.

By doing the above you have less chance to miss a blem in the boat. Once everthing is sanded it's much harder to see any blem or gouges in the surface.

7] Prime the whole hull. This is 4 coat's of Awlgrip 545 White.



8] After that has flashed off well add a contrasting color for a guide coat. Krylon spray bomb paint work's fine, misting it.





The next day you can start blocking the primer with 320gt wet sanding it. The guide coat will help a lot here. You can see what your doing and really help's getting the surface fully sanded flat.

9] Wash the hull again with Wax&Grease remover

10] Now it's ready to shoot. Tack off the hull with a tack cloth. It really doesn't take that much paint with Awlgrip to cover the hull well. This is a 25ft Mako. It's painted from the chine to the rub rail. 1qt of color [off white revisited is a damn close match to the original gellcoat] 1qt of Awlcat #2 and reduced 25% covered the whole thing with 4 coat's. Spraying Very thin coat's and waiting 45min between coat's.