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  • Tips and tricks

    So, Headcase had a good idea. Im sure its probaly been done before, but im going to create a thread that gives good tips and tricks to help out out fellow classic Mako owners. Not everybody knows what to do but here we can help. Anything that has helped you and want to share, please by all means, post away. I hope it takes off. Ill start.

    1: when youre dealing with bare fiberglass and you are going to spray gelcoat. Keep a bondo spreader with you. Mix up your batch and save a small amount to the side. Just before you spray, use the bondo spreader by spreading the mix into all the pin holes. Then spray your part. You have to wet sand anyway. This saves a lot of extra time on the back end.

    2: when grinding out cracks in fiberglass, or in a damaged area, make sure you grind every bit of the delamination out no matter how far it travels. If you dont, the crack will return. Its just a matter of time.

    3: there is a trick to shooting beautiful nonskid. To achieve professional results, at least when using Awlgrip, mix both fine and rough particles together into the paint. Let sit for at least 15 min so that the nonskid particles absorb the paint. Then mix again. I like to place a couple of 3/4 nuts in the pot to shake the entire time Im spraying. Now, the trick. You can not spray like normal paint as it gets too heavy and takes on a wet look. You dont want this. Keep a greater distance from the deck. Like 15 or so away. Once sprayed, stand back and mist the entire surface and this gives the perfect nonskid. Trust me when I say, this takes practice.

    4: dont make templates with cardboard. I mean, you can, but go buy a sheet of door skin plywood. Cut into 2.5 wide strips and you can cut with scissors. Using a hot glue gun to make the joints, it wont flex or fall apart.

    5: when replacing the stringers in your boat. Take the boat off the trailer. Let the keel rest on the ground. Preferably on a concrete slab of sorts. Block and level the boat. Leaving on the trailer could possibly allow the boat to be left in a bind and end up with a warp or twist. Not good. If it has to stay on the trailer, take the extra steps to ensure its perfect before you cut them out to replace.

    6: working with wood or plywood is a bit out dated. But its cheaper as well. You cant use regular pine from home depot or Lowes. First, it has to be marine grade. Second, at least 7 ply. Like fir. Third, not treated marine plywood. Side note; resin wont stick to ceadar. It will release. Ask me how I know. Before you fiberglass to wood. Thin your resin by 50% with acetone. Saturate the wood with several coats of this batch of thinned resin, along with the proper amount of MEKP. Once its cured, it will remain very tacky. Start laying up your glass with regular mixture of resin. Use a fiberglass roller. Smaller the better as it works the air bubbles out. Any area that water can get through, like a rod holder or through hull, I cut an over sized hole and fill with fiberglass. This is an extra step but if your part goes through glass and not wood, if there ever is a leak, it wont rot out the wood.

    7: if you have to run wires and its a pain and A year later you want to run a new wire or cable, always leave a chase wire or 1/4 nylon rope in the channel tied on either end. Sure is a lot better than running a snake over and over again.

    8: remember, paint work is about 5% of your project. 95% is sanding and prepping. If you feel it, youll see it in your finshied product. Take your time and dont rush it. If you do, it wont turn out well and youre not gonna be happy.

    9: dont use bondo. It shrinks over time. Use 3m premium marine putty. You can gelcoat over this product as well. A little hard to sand but worth it in the end. Awlfair is a good choice as well.

    10: before you spray your paint. Use a low sticky tack cloth. Not the super sticky ones. These leave residu if youre not carefull and your paint will either fish eye or separate due to this.

    I hope some of these will help you on your journey. Good luck to all.
    BadMako.[br]

  • #2
    So A few from me regarding spraying gelcoat/duratec:

    1. The purple harbor freight spray guns work pretty well to spray duratec/gelcoat if you drill the nozzle out to 2mm (they usually come standard 1.3-1.4mm). I use a 5/64" bit. Guns are too cheap not to have extra new ones on hand. I prefer to uses a new one for every spray job.

    2. You can help speed up cleaning time and maximize spraying time with the HF gun if you use the disposable cups that screw on top. I change out every time I stop to clean gun, usually after spraying 60oz continuously in 20oz batches.

    3. Duratec mixed to recommended 50/50 with gelcoat is super thin and will run like crazy. I've had good success with maximum 35% Duratec. Won't sag at proper coat thickness on vertical surfaces in optimum temps. Will still harden.

    4. Use the disposable paper cups and pre measure out all your gelcoat/duratec so you can catalyze and put into sprayer immediately. Don't try to reuse the mixing cups.

    5. Buy a full face 3M respirator. You spend thousands on your boat project, your lungs and eyes are worth a few bucks.

    6. Buy a full face 3m respirator. Yes I said that twice. Use it.

    7. Use the old transparency film used on overhead projectors-(remember them?) to create disposable face shields for the full face respirator then tape them on. When it gets difficult to see, just replace with new transparency film.

    8. If you plan to spray alot of gelcoat or paint(like the inside or outside of a hull), borrow an extra compressor. Better to have two sharing the load and if one craps out at worst possible time you can still keep going.

    9. Surface prep for gelcoat should be 120 grit maximum. Waste of energy to go finer and the gel will cover scratch marks easily even at 60-80 grit. Save your sanding energy and high grit for the sanding you will need AFTER spraying the gelcoat. Coarse grit actually helps create more surface are to improve bond between old and new gelcoat. Ignore this for paint. Paint will not cover coarse grit.

    10. Most spray problems are due to environment, improper mix prep, and moisture in airline. Don't spray when its too hot/cold/windy/high humidity. Basically if you cant stand the climate, the gelcoat will not like it either. Of I cant spray relatively comfortably in a full tyvek coverall, then its too hot to spray. Air compressors generate huge amounts of water in the airlines. Use water separator on tank prior to airline and disposable filter on gun(new filter on gun every day). I bet moisture ruins more spraying than any other issue. Be precise with your measurements when mixing. Don't eyball it. I use cheap pyrex measuring cups, scales, and a self measuring catalyst dispensers. I premark the disposable cups with mix level lines. All worth their weight in gold.

    11. Use Duratec gelcoat additive only when spraying an air exposed surface with gelcoat. Dont use duratec in molds and dont spray raw gelcoat on air exposed surfaces. Mix Duratec with no wax gelcoat only. Don't use waxed gelcoat, its a pain in so many ways I can't even begin to start listing them all.

    I'm sure there are more, but this is what's worked for me after much cussing, wasted materiel, and learning from others over the years.

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    • #3
      Thanks for the time on adding these tips
      1984 Mako 238 WA [br]2015 Suzuki 250 APX[br]Central PA/OCMD[br]http://www.classicmako.com/forum/topic.asp?TOPIC_ID=35081[br]

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      • #4
        Great post, thanks for the tips! When drilling out the purple harbor freight gun orifice, is it only the center-most post that is widened. I like those guns a lot and used two to spray a two-part epoxy coating onto a 20' flatbed trailer. I had fisheyes from too much moisture in the air and lines but for a utilitarian trailer with no surface prep, it came out ok.
        Texas[br]\'76 Mako 23- A work in progress[br]

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        • #5
          When drilling out the purple harbor fright guns, you just need to drill the orifice in which the needle controlled by the trigger seats.

          This is the same orifice that all of the paint or gelcoat comes out when you pull the trigger.

          You do not need to drill the removable fan tip that you adjust the spray pattern.

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