Lapstrake fairing prior to painting

[59seaskiff]

Hello,
I have a 57 (clinker built) Lyman 16.5 foot runabout in sound condition that needs only cosmetics. My question for this thread is that the existing paint is sound, but along with hollow surface spots and some ragged edges to the strakes due to dock abrasion (most still coated with sound paint), I need to use a fairing compound to make them look their best once again.

I planned to use West System epoxy with 410 microlite fairing filler to do this. However I have read in some forums that this might not be best for the dry plywood underneath. The boat has not been in the water for 20+ years. Thus I wish to get confirmation on the best approach for this purpose. Are there other fairing compounds that I should consider? Do I risk cupping (warping) of the planks when the wood expands? I would estimate that the depth of the defects to be faired is minimal along the plank's length, with interupted spots at the edges that run as deep as 1/8 inch.

Suggestions please?

 

[Woodonglass]

Re: Lapstrake fairing prior to painting

If they are no deeper than 1/8" then my opinion, based on research and experience, is for wood boats, epoxy based fillers with glass bubbles will be your best bet, especially for abrasion prone areas. Prep by washing with TSP and allow to dry for 48 hours then wipe down with Acetone then heat gun to expand the wood then apply the filler. I'd also precoat the wood with epoxy prior to filling with the fairing material. I'd apply the fairing material when the pre-coat started to tack up.

 

[59seaskiff]

Re: Lapstrake fairing prior to painting

Thanks very much for the reply.. So apparently you do not see issues with using epoxy on these strakes to any detriment of the wood? Or is that why you recommend heating the wood to swell it prior to epoxy application?

 

[Woodonglass]

Re: Lapstrake fairing prior to painting

Wood Always Expands and Contracts with varying temps. That's why epoxy is the chosen resin. When cured it remains very flexible and will expand and contract along with the wood. I recommend heating the wood to open it's pores to allow the resin to penetrate as deeply as possible to give the best possible adhesion.

 

[Yacht Dr.]

Re: Lapstrake fairing prior to painting

Hello,
I have a 57 (clinker built) Lyman 16.5 foot runabout in sound condition that needs only cosmetics. My question for this thread is that the existing paint is sound, but along with hollow surface spots and some ragged edges to the strakes due to dock abrasion (most still coated with sound paint), I need to use a fairing compound to make them look their best once again.

I planned to use West System epoxy with 410 microlite fairing filler to do this. However I have read in some forums that this might not be best for the dry plywood underneath. The boat has not been in the water for 20+ years. Thus I wish to get confirmation on the best approach for this purpose. Are there other fairing compounds that I should consider? Do I risk cupping (warping) of the planks when the wood expands? I would estimate that the depth of the defects to be faired is minimal along the plank's length, with interupted spots at the edges that run as deep as 1/8 inch.

Suggestions please?

Yup .. epoxy is gonna be your resin base ..

Post cure ( meaning make sure that the resin/glass/filler ) is nice and hard .. I mean HARD .. wait till it does its cure. Sometimes you have to heat lamp it to post cure before you Prime.

Yes.. Prime with 2 part epoxy primer for the best outcome.

Yes you can risk cupping or expanding for your planks/joints .. but its kinda hard to tell. Its a hit and miss kinda thing when your Filling with one product onto another ( filler against wood etc... ).

Use your best judgement when things are dry.

YD.

 

[59seaskiff]

Re: Lapstrake fairing prior to painting

Very grateful for the thoughtful responses. I will post more as I proceed. Perhaps offer some pics.
One further point of clarification: Since the old paint is sound, I had not planned on stripping it completely, But I have begun sanding, and it is clear that there will be many places where I am down to bare wood. What sealer should I use that can go over the sanded paint as well as the bare wood?

 

[59seaskiff]

Re: Lapstrake fairing prior to painting

Maybe I should reword that last post to ask if pre-wetting the planks w/unfilled epoxy can also go over the top of sanded paint that did not get removed on the same plank?

 

[Woodonglass]

Re: Lapstrake fairing prior to painting

It can but...The adhesion of the epoxy will only be as good as the adhesion of the paint. For any repairs, I'd recommend the removal of as much of the paint as possible to allow the epoxy to adhere properly.