86 Mirage rebuild

[1986Mirage]

Hi all, I could use a bit of guidance with my boat rebuild.
The boat: 1986 20ft mirage fish/ski. Beam is about 8.5 ft. Powered by a Stern drive 230MR.
Full stringer/transom rebuild underway. Have all the old stuff out. Complete removal. No wood left in boat. Ready, almost to put in transom.
Transom original thickness was 2" for 2' around the outdrive. 2* 3/4 ply plus 1/8 outer layup and 3/8 inner layup. Rest of transom had 1/2 plywood with the same fiberglass thickness.
I am adding a kicker motor to one side as well as making a new aft platform. Thus, I'm making the whole transom 2" thick (2* 3/4 meranti plywood) and adding some stringer ties from the transom. Trying to add pictures, but I'm not able to with the tablet. I will do with the computer on Monday.
My questions for now are, do I epoxy glue the first layer of plywood to the outer fiberglass? The surface of the fiberglass is very uneven. My concern is getting enough epoxy glue on there and clamping the plywood, all before it sets up. Where I live, the temp does not allow a slow set epoxy.

My other fear is that I deflect the plywood to much, thus causing a stress on the plywood to fiberglass bond when I remove the clamps. Do you think this is a reasonable fear?
The transom is such I will have to laminate the plywood in the boat.
Any advice is much appreciated. Thank you in advance.

[lawtoolguy]

Hello,

Sounds like you have gotten allot of the dirty work completed. I'm not an expert but I can pass on what has been shared with me while doing my transom. Once you have all the old wood ground down to outer layer of glass you'll want to get everything in place. Coat first layer of new plywood with un-thickened epoxy and set it aside. Mix up your thickened epoxy to peanut butter consistency with wood flour.Apply to your inner layer of glass with a 1/4 inch notched trowel then do the same to your 1 st layer of plywood. Once they are sandwiched together you will have a good buildup of glue. Then clamp them tight enough to allow for a little to ooze but not to tight that all the glue comes out. I used 1" x 6" boards on inside and outside threw bolted in existing holes to clamp my layers. Make sure you wrap the bolts with clear tape to make for easy removal. To fill the gaps around edges I used thickened epoxy with wood flour and milled glass. My surface was slightly uneven and had some dry spots in the old glass that filled with thickened epoxy before starting. It really helps to have everything in place and tested and also an extra person for mixing. You will Fill bolt holes that are not needed later with thickened epoxy. There is allot of good info here. I think I spent 2 days reading links before even getting my materials together

Hope this helps

[1986Mirage]

Thanks for the quick reply! Yes, that information helps alot. I had been reading the tutorials on here, but had overlooked that last little piece.

Ordered all the epoxy and what not from the website today. For some reason, I'm not able to post pictures. It is probably a setting issue on my computer or something.

in anycase, once i figure out how to post the pictures (maybe I need to resize them?) I will post how it turns out and any questions along the way I run into.

[1986Mirage]

Maybe someone could help with a lamination schedule for the stringers and transom?

Transom: 2" thick total. 2*3/4" plywood. Outer skin was 1/8" thick. Inner skin was 3/8" thick.
Stringers: 1" thick total. 1 piece of 3/4 plywood with 1/8" thick on either side.

Also, how many layers of biaxial 25oz tape would you recommend on the stringers to hull and transom to hull?

Still trying to figure out the pictures

[1986Mirage]

Ordered all the epoxy and what not yesterday. To my surprise, it all shipped within a couole hours.

See if this works for some pictures...they may help with the laminate schedule.
http://gallery.bateau2.com/albums/userp ... 3254~0.jpg

http://gallery.bateau2.com/albums/userp ... 943338.jpg

http://gallery.bateau2.com/albums/userp ... 332866.jpg

http://gallery.bateau2.com/albums/userp ... 613887.jpg

[1986Mirage]

For those of you whom are as technically challenged as myself. To post a pic from a droid phone, you have to first resize the picture by sending it to yourself. Then go to the builder forums and upload the file, one that isn't 4.5 mb .
You can then paste a link in the comment section.

[pee wee]

You almost had it- after you paste the url into your message, highlight it and hit the Img button. Do a preview of your message before you hit submit, and it should show as a photo.

[tech_support]

Transom: 2" thick total. 2*3/4" plywood. Outer skin was 1/8" thick. Inner skin was 3/8" thick.

That is an abnormally thick inner skin

More typical of a boat that sixe is 1/8" t0 1/4" inside skin. To rebuild that thickness you will use approximately 3 layers of 1708. Perhaps they just used a ton of matt in there

Stringers: 1" thick total. 1 piece of 3/4 plywood with 1/8" thick on either side.

It would be easier for you to just use two layers of 1/2"

Also, how many layers of biaxial 25oz tape would you recommend on the stringers to hull and transom to hull?

i would use something lighter like 2 x 12 oz of maybe 1708 tape at the max. If you are wrapping the stringers with cloth (overlap to the hull) then you can use less tabbing

If it were mine, I would tab with 2 layers 12 oz biax then wrap with one layer of 1708

[1986Mirage]

Thanks for replies gentlemen. It looks like someone else has opened up this boat. Maybe they added extra to the inside skin? In any case, I'll let you know how it goes, all the supplies should arrive by Monday .

[1986Mirage]

Has anyone seen an msds for the marinepoxy? In the northwest the temp is fluctuating to the point of needing to heat the shop while the marinepoxy is kicking. My heat source is a wood stove. Want to be sure I don't burn down the shop with an open flame source. Of course, I will keep it ventilated. Thanks in advance to the replies.