Help removing outboard tub

[Cadwelder]

Re: Help removing outboard tub

Yes, yes, yes on the CSM, polyester resin alone is not a good "glue". If you were using epoxy you'd be okay, but with the polyester you need a layer of CSM between the layers of plywood. When you get ready to set the transom into place you can do it with 2 or three layers of matt and resin. You'll need to precoat the wood first to make sure you don't have dry spots. The layers of CSM depend on how smooth and flat your outer skin and plywood are.

As far as the old engine mounting holes, you can use the thicken "peanut butter mix" but I really don't see the need, your outer skin is only 3/16 to 1/4" thick, and when you clamp the transom in place the mat and resin will fill those holes just fine. I would even put a piece of slick plastic over them during the clamping so a lot of resin don't run out of them and just fills them up smooth.

Now on the clamping, make sure you have your clamping method ready to go, and make a trial run installing it before you mix your resin, you won't have time to fumble around, looking for clamping blocks and adjusting things once the resin is mixed. And of course have your matt precut and ready to go as well.

 

[molo_30]

Re: Help removing outboard tub

Ok, I spoke to the guys at the local fibreglassing shop and was told all I would need is poly resin and cabosil. So this is what I have done, thickened it up and spread evenly, weighted it down and cleaned up the excess squeezing out.

I am going to put two layers of mat between the ply and the existing transom outer, then more thickened resin followed by the ply being clamped.

I am going to use the existing holes for clamping and use four pieces of straight hardwood with 3 bolts in each, two pieces inside and two outside to pull it all in.

I can't really do much about the lamination now?

 

[Cadwelder]

Re: Help removing outboard tub

Ok, I spoke to the guys at the local fibreglassing shop and was told all I would need is poly resin and cabosil. So this is what I have done, thickened it up and spread evenly, weighted it down and cleaned up the excess squeezing out.

I am going to put two layers of mat between the ply and the existing transom outer, then more thickened resin followed by the ply being clamped.

I am going to use the existing holes for clamping and use four pieces of straight hardwood with 3 bolts in each, two pieces inside and two outside to pull it all in.

I can't really do much about the lamination now?

Be sure to wax the bolts you put thru the transom as clamps and try to have only the shank part in the wood with all the threads on the outside clamping blocks, this way resin doesn't get in the threads and bond the bolts to the whole transom. Makes them much easier to remove.

True you can't do much about the laminate now, so just continue on....

Two layers of matt between the outer skin and plywood is okay, (three won't hurt anything) it all depends on how true (flat) everything is.

 

[molo_30]

Re: Help removing outboard tub

Ok, finally did the dry fit and will bed it in with resin this afternoon.

Hopefully all goes well.....

 

[molo_30]

Re: Help removing outboard tub

Thank god thats done. Kept it light on the hardener so I had extra time and it worked out well.

 

[molo_30]

Re: Help removing outboard tub

Well finally put a couple of layers over the transom. One layer of csm and one layer of woven roving. Will put another layer of woven to finish it off.

Next will be the stringers then the floor.

Any tips for the stringers?

 

[Woodonglass]

Re: Help removing outboard tub

Here's a drawing of how I recommend doing stringers. Use 1/4" dowels to hold the Stringers up off the hull while you squirt the PL under them. It takes 48 hours of the PL to cure. Don't attempt to tab the stringers in before the PL cures. Remove the dowels before tabbing. Again, are you planning on building some Knee Braces for support?

(Click the image to enlarge)

 

[molo_30]

Re: Help removing outboard tub

Thanks for the pic. Heaps easier to get the message across like that.

I will be putting four knee braces where the stringers meet the transom for strength.

Any ideas on how to 'squirt' the PL? I was going to use a bag from the glass dealer where you snip the end off like a cake decorator, only he says it quite messy. Also any ideas on how to support the stringers until the PL sets?

 

[Woodonglass]

Re: Help removing outboard tub

PL is a Construction Adhesive that comes in Tubes from Lowe's. You'll need a caulking gun. I use 1/4" dowels to hold the stringers up off the hull while the PL sets. It takes 48 hours. I remove the dowels after. I use a Large Plastic or teflon spoon dipped in Paint thinner to Cove the PL to the stringer and the Paint Thinner keeps it from sticking to the spoon and smooths the PL really nice.

 

[molo_30]

Re: Help removing outboard tub

Woodonglass,

please excuse my lack of knowledge here but what type of adhesive is it? I only ask as I wil go down to my local Bunnings (Lowes equivalent) and see what they have the same as I am not sure they will have the same brand.

Also will the glass have no trouble sticking to the adhesive?

 

[molo_30]

Re: Help removing outboard tub

Woodonglass,

please excuse my lack of knowledge here but what type of adhesive is it? I only ask as I wil go down to my local Bunnings (Lowes equivalent) and see what they have the same as I am not sure they will have the same brand.

Also will the glass have no trouble sticking to the adhesive?

Anyone?

 

[Woodonglass]

Re: Help removing outboard tub

Did you NOT see my reply with the Picture in post #29. It is a Polyurethane 100% waterproof Construction Adhesive. Used to glued plywood panels etc.. in the contstruction industry. ANY home center will carry it made by various MFG's Just make sure it is 100% waterproof. I MUST cure and COMPLETELY Skin over before you can Glass over it. That usually takes a MINIMUM of 48 hours. It NEVER gets HARD it remains spongy when totally cured.

 

[molo_30]

Re: Help removing outboard tub

Ok then.

 

[Greg Mrozinski]

Re: Help removing outboard tub

Just FYI. Thin applications of PL will cure in about 48 hours, but heavy thicker applications (gap filling, fileting, etc.) will take a full 72 hours to cure. You should also dampen the surfaces with water first before gluing. It promotes the curing of the PL.

 

[molo_30]

Re: Help removing outboard tub

Thanks for the heads up.

 

[molo_30]

Re: Help removing outboard tub

Hi guys,

been awhile since my last post. Funny how time flies when kids are involved.

I have finished the transome now and have ripped the floor out revealing that the whole three stringers are shot. Would it seem that I will have to cut the whole of the storage area at the front of the boat out to get to them as in the picture?

Also in regards to tabbing in the stringers to the transom, is my crude pic attached basically what I need to do to spread the load from the transom to the stringers? Is it ok to make the tabs from the transom forward about 1000mm and tab them into the new stringers that I am using?

Thanks guys,

Cheers.

 

[molo_30]

Re: Help removing outboard tub

Any ideas guys?

 

[molo_30]

Re: Help removing outboard tub

Well I finall cut the outer stringers and put them in. As the length from the transom to the forward bulkhead is 2550mm and I can only get lengths of marine ply at 2400mm I had to join the lengths. I went about 1000mm forward of the transom for the join.

I used polyurethane construction adhesive made by sikaflex as recommended on here as you can see in the photo it is a grey coloured glue. Next is the inner stringers. One question I have is that at the front of the boat is three stringers. The outer two bend toward the bow and meet in the middle. Any ideas on how to get the 3/4" marine ply to bend around the radius and stay that way so it can be glued in?



You can see the last layer I layed on the transom went off too quickly (way too much hardener) so I ended up having to grind out a heap of air bubbles which will be fixed on the final layer.

 

[Woodonglass]

Re: Help removing outboard tub

The way you joined your stringers is not a very good method. It would have been much better to have butted the two ends together and then used two 24" pieces of 3/8" plywood on either side glued and screwed to hold them together. Your method could allow them to flex a bit too much. Time will tell. Sorry to hear about the Transom. How much curvature is there in the bow stringers? Pics would help us to help you.

 

[molo_30]

Re: Help removing outboard tub

I will get a photo of the front uploaded so you can see what I mean.

As far as the stringers go, my understanding was that the strength was in the glass over the ply not the ply itself? I have read lots about people using foam for stringers which enforces my understanding but correct me if I'm wrong as I am very new to this. If I lay extra glass over the join would this negate the issue?