Richard_Blake
New member
Edith's topside seams almost clear for caulking, now (at last! horrible job). They look dauntingly like mountain crevasses. Planks have shrunk an average of 2mm each in width. We've discovered there are no caulking bevels - either one plank is bevelled right back to inside edge, or the planks have been cut square and the curve of the hull has served to provide wedge-shape, as it were. Sadly, on about 50% of seams, previous caulkers have driven cotton straight into plank edges rather than bewteen them. Much work now going into repairing the splits and shaving out the old splinters. First unexpected horror we've found.
Professional caulker working on nearby boat will do the bulk of the caulking, and is keeping an eye on our seam preparation. We tease out oakum in the evenings in front of the television.
So - the questions: Putty recipes.... I've looked back over old posts, and through old CB, PBO, WB etc. articles, but could use further advice.
Putty in topside seams should presumably remain pretty flexible. Tallow? How much?
We can get putty, whiting, tallow, raw linseed oil - but not white lead in any form here in the NL (and postage for lead.....!) - however we have a large quantity of red lead powder bought quietly a couple of years ago. We know the primer we have will cover the red lead without bleed-through. We plan to use the same primer on the seams before and after caulking with red lead mixed in.
What putty recipes/mixing proportions does the panel recommend?
What are the functions of the various ingredients - what hardens it, what keeps it flexible? Is the (red) lead just poison, or also a softening agent?
Should we make the mixture as stiff as possible or fairly squishy with linseed oil?
Although we lean towards traditional putty, our caulker is strongly against it ("It always hardens too much eventually especially in wide seams, and you've just found out how hard it is to get out, even when it's not doing its job anymore!")
He recommends a Shell product called Tixophalte, a rubberised bitumen adhesive, which supposedly even sticks to wet surfaces underwater, and keeps its slightly flexible consistency through a wide temperature range. It's apparently not like a Sikaflex-type product, but a modern version of pitch. Sticks to anything, but is fairly easy to remove for repairs. Recommended for a range of functions, from sticking roofing felt to temporary repairs of plumbing.
We're going to call around a few people here who have apparently used it on traditional boats - and we hereby submit the suggestion to the panel for consideration and comment! The technical details are available on (eg.) ww.yalteks.com , English translation pages, under Shingle Supplementary Products.
All the best,
Richard
<hr width=100% size=1>LowTech
Professional caulker working on nearby boat will do the bulk of the caulking, and is keeping an eye on our seam preparation. We tease out oakum in the evenings in front of the television.
So - the questions: Putty recipes.... I've looked back over old posts, and through old CB, PBO, WB etc. articles, but could use further advice.
Putty in topside seams should presumably remain pretty flexible. Tallow? How much?
We can get putty, whiting, tallow, raw linseed oil - but not white lead in any form here in the NL (and postage for lead.....!) - however we have a large quantity of red lead powder bought quietly a couple of years ago. We know the primer we have will cover the red lead without bleed-through. We plan to use the same primer on the seams before and after caulking with red lead mixed in.
What putty recipes/mixing proportions does the panel recommend?
What are the functions of the various ingredients - what hardens it, what keeps it flexible? Is the (red) lead just poison, or also a softening agent?
Should we make the mixture as stiff as possible or fairly squishy with linseed oil?
Although we lean towards traditional putty, our caulker is strongly against it ("It always hardens too much eventually especially in wide seams, and you've just found out how hard it is to get out, even when it's not doing its job anymore!")
He recommends a Shell product called Tixophalte, a rubberised bitumen adhesive, which supposedly even sticks to wet surfaces underwater, and keeps its slightly flexible consistency through a wide temperature range. It's apparently not like a Sikaflex-type product, but a modern version of pitch. Sticks to anything, but is fairly easy to remove for repairs. Recommended for a range of functions, from sticking roofing felt to temporary repairs of plumbing.
We're going to call around a few people here who have apparently used it on traditional boats - and we hereby submit the suggestion to the panel for consideration and comment! The technical details are available on (eg.) ww.yalteks.com , English translation pages, under Shingle Supplementary Products.
All the best,
Richard
<hr width=100% size=1>LowTech
