Bondo on Transom?

[zachgry]

I have removed my transom and between the plywood and shell it looks like a thin layer of what looks like bondo. On my stringers they were coated with something that has a greenish tint to it but the transom is differant. What could it be and do i need to grind it all off of the transom. I was going to put the transom back in with epoxy and im not shure if i need to remove this or not. Also I have been sanding were the stringers were but how much sanding should i do Do i need to remove all the old epoxy down to the shell or just cleaned up. I am trying to get my transom back in in the next day or two so please help. Thx..

 

[Bob_VT]

Re: Bondo on Transom?

I hope it was not bondo since that is really not a glue/adhesive.

Yup spend some time to get all the old junk off but do not grind into the fiberglass.... just get the crud off. If it is unknown crud wear a mask!

 

[Yacht Dr.]

Re: Bondo on Transom?

Hello Zachgry..

I agree with Bob..

Think of it this way with any repair..unless you built it..you have no idea. Can you be sure that the filler is Bonded well ?..glass over that and you have multiple failing points.. the filler to skin..filler within itself and non-compatibility with resin/glass over it.

Always grind till you hit glass to prep for new glass on..

Stringers.. Get all the shine off before beginning ( use mat for your first layer even if your cloth has mat backing ).

YD.

 

[57chris]

Re: Bondo on Transom?

Sounds like someone used Kitty Hair. It's a bondo like product, green in color, has many names, we used to call it kitty hair, but basicly it's bondo with fiberglass strands in it...IMO it's not acceptable as a replacement for fiberglass as it soaks up water like a sponge, but I found it all over my boat as well from the PO's attempts of repairs.

 

[Mark42]

Re: Bondo on Transom?

Don't count on color to tell you much. For example, the resin in my Bayliner for stringers is pink, the resin for the hull is the traditional amber, and some putty/filler stuff that seals the cap to the hull, looks like bondo, is pink too, but its hard as a rock.

If what you found is OEM, I doubt its a body filler type material.

 

[ondarvr]

Re: Bondo on Transom?

If this putty was from the factory, then its a corebond type product used to bond the transom wood in place. These types of products have become more common, they're used to bed all types of cores, stringers, liners, backing plates or anything that needs to be held tightly in place. The color can change from brand to brand, or depending on whether clear or red catalyst was used it may be gray or pink. Its nothing to worry about and doesn't mean they used substandard products in the construction.

 

[zachgry]

Re: Bondo on Transom?

I kinda misspoke. The color green i was talking about is on the stringers and when i sand its kinda clear but has a green tint to it. But the transom has a 1/8 thick coat over the intire transom were the plywood was supposed to be glued to. It is a light gray and very hard. I can take a flat screwdriver and chip come of it off but it looks like i will be hours and hours sanding. Anyway thats why i said bondo. Thanks guys for the tips.

 

[zachgry]

Re: Bondo on Transom?

Yacht Dr, Please explain..
( use mat for your first layer even if your cloth has mat backing ).
And how do i find out if my boat is been done with poly or epoxy. Can i use poly? or do i need to use epoxy? I will be ordering my materials today and i am lost. I am replaceing stringers and transom in a 1974 Glastron Runabout and while i get the basic idea on how i am lost on what epoxy or poly and mat or cloth i should use. If you have time can someone please give me info on what the materials i should use. I would hate to spend money ordering something i cant or shouldnt use.

 

[Mark42]

Re: Bondo on Transom?

Yacht Dr, Please explain..
( use mat for your first layer even if your cloth has mat backing ).
And how do i find out if my boat is been done with poly or epoxy. Can i use poly? or do i need to use epoxy? I will be ordering my materials today and i am lost. I am replaceing stringers and transom in a 1974 Glastron Runabout and while i get the basic idea on how i am lost on what epoxy or poly and mat or cloth i should use. If you have time can someone please give me info on what the materials i should use. I would hate to spend money ordering something i cant or shouldnt use.

Your Glastron was made with polyester/vinylester resin. Poly will work fine. I never heard of not using fabrics that have mat on one side with poly. But I have read where it is suggested, and easier to deal with than mat alone.

 

[jonesg]

Re: Bondo on Transom?

if in doubt put a grinder to it, smell the difference between epoxy and polyester resins.

 

[ondarvr]

Re: Bondo on Transom?

There is no doubt, your boat is made with polyester.

What YD is saying is that you need to use mat between each layer of any type of woven or stitched glass. Frequently mat will be used as a first layer on a new surface because it will conform much better to any irregularities, the mat stitched to fabrics can be thin at times and not be as easy to work with. If the woven or stitched product has mat attached to it, you don't necessarily need to use more mat though.

 

[Yacht Dr.]

Re: Bondo on Transom?

Yacht Dr, Please explain..
( use mat for your first layer even if your cloth has mat backing ).
And how do i find out if my boat is been done with poly or epoxy. Can i use poly? or do i need to use epoxy? I will be ordering my materials today and i am lost. I am replaceing stringers and transom in a 1974 Glastron Runabout and while i get the basic idea on how i am lost on what epoxy or poly and mat or cloth i should use. If you have time can someone please give me info on what the materials i should use. I would hate to spend money ordering something i cant or shouldnt use.

Sorry for the delay..was working

Yup..your boat is made from polyester.

Materials needed. Aside from your safety gear.

1. enough 1.5 oz mat for first layer on layups. ( It helps air bubble issues in your lams..but more importantly .. IT is used for Your initial BOND. )

2. poly resin with mekp ( mek dispenser bottle helps alot for 10 bucks )

3. cabosil

4. acetone

5. 4"x1/4-1/2 inch bubble roller ( resin roller )

plus all your other sundries .. spreaders, buckets, brushes..ect.

oh yea..beer too

YD.

 

[ondarvr]

Re: Bondo on Transom?

( It helps air bubble issues in your lams..but more importantly .. IT is used for Your initial BOND. )

The only time it will improve the bond is if the substrate has an irregular surface that the CSM attached to the fabric can't fill on its own, on a smooth surface it won't make a difference.

 

[Yacht Dr.]

Re: Bondo on Transom?

Just a difference in opinion

For reference .. if your going to build a repair up with .. lets say 18 oz woving roving without backing..you would start with 2 layers of 1.5 oz mat..1.5oz mat between lams and finish with 2 layers of mat as well.

I would not trust 3/4 oz mat to start my bond off with ( the mat on 1708 ).

Mat IS for bonding fiberglass .. do not use cloth without it m8s..

YD.

 

[ondarvr]

Re: Bondo on Transom?

Two layers of mat will not bond better than one. The only time more mat will help is if the surface is shaped so that it's difficult for woven or stitched products to follow the contours. This helps to reduce any resin rich areas that may form in the laminate, it does the same thing when used between layers of roving and other similar types of glass. That's why if the surface is smooth there is less need for a heavy layer of CSM. The actual resin bond is the same with or without CSM.

Mat builds bulk, thickness and stiffness and far less strength, mainly because of the higher resin content, higher resin content means a weaker, heavier part.

The reason more CSM is used in skin layers is to reduce the print through of continuous strand products that hold less resin, which results in more noticeable shrink. A resin rich layer can also be more water and chemical resistant.

The reason for finishing the repair with extra mat is for cosmetic purposes only, except if its below the water line, then it may help as I indicated above.