repairs to bulkheads

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pandos

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The main bulkheads have some water staining and various screw holes, marks etc. I intend to reface them by putting on 4mm. mahogany faced marine ply. (self adhesive veneers are not available over here.)

My preference would be to cut the ply at home apply varnish etc and then stick this new facing onto the already varnished bulkheads.

Question, should I use contact adhesive and thus render the entire operation instant without the need for pins etc. or......

I could use flooring adhesive which will stick anything to anything ( I have used it to stick stainless steel to mdf) and is repositionable but has very little grab and needs to be pressed into position consistently for about 20 minutes.

Has anyone tried this before, it seems too easy a solution to transform the appearance of the saloon so drastically,

Regards
 
I thing you will have problems cutting at home and expecting a perfect fit.
I suppose staples with a piece of copper wire beneath them would hold the panel in position.

There are contact adhesives with low tack and repositionable
 
Bobobolinsky said:
I thing you will have problems cutting at home and expecting a perfect fit.
Click to expand...

My intention is to make paper templates for each piece, getting them in through the hatch will be potentially the biggest problem so the smaller the better,

I can do a little trimming on board with a plane or some of sandpaper.

I do not understand the reference to staples and copper wire??

Regards
 
It is a compromise between contact adhesive where you let it dry before banging on the new ply and you can't reposition it versus using the floor glue where you can reposition the plky but it won't hold up so you have to clamp it. I would suggest you investigate the posibility of clamping or applying pressure from struts etc. Another alternative is to try various glues to see if you cna find a reasonable compromise gripping time. good luck olewill
 
Personally I would rethink the ply and consider a thinner veneer. At the risk of disclosing a secret, the outside of TGs coachroof is veneered following splining of some shakes in original substrake which whilst robust in terms of structure were unsightly. so on the recommendations of the surveyor I purchased some think veneers from Robins of Bristol, some epoxy and pins. The result was very successful. The veneers were glued using epoxy and pins which were later removed and filled and are pretty unseen except for detailed scrutiny. I think one of the contributions to ease of doing this was that the epoxy gave us time to position the veneer whereas contact adhesive would not. The issue is of course, do you want this ease of working or no pin holes. Each side of TG is done using 4 sheets of veneer and the joins are almost undetectable.
 
Thanks for the replies,

I like the idea of a repositionable contact glue but does anyone have a brand name for one.?

Using non sheet material is not likely to be effective, the panels are 47inches wide and they need a pristine finish, I can mitre a quadrant along the outer edges if the fit is not seamless.

The chances of bonding veneer onto the bulkhead and achieving a good finish are slim, particularly where it would be impossible to sand right up to the edges once in place.

Regards

Tony
 
You could fix them using Sikaflex which has excellent holding power, is flexible and gives a fair amount of initial movement to position accurately.
Suggest you spread it with a notched tiling trowel or similar and then wiggle the panel up and down as well as side to side to ensure good contact before final positioning.
Copious use of strategically placed Duck tape should hold the panels in position until the Sika has gone off.
Best to use Sikaflex EBT available from Screwfix which is the same as Sikaflex 291 but less than half the price.
The '9' in Sikaflex 291 indicates marine and seems to be the reason the 291 cost at least twice as much as the EBT.

Rgds
Richard
 
Personally I would be very cautious about relying on a paper template for something that size. As a thought though, if you Google "tick stick", it may give you some ideas for a way of getting some measurements to use to with your paper template so that you can double check things before you cut your ply.
 
Rigger Mortice said:
Personally I would be very cautious about relying on a paper template for something that size. As a thought though, if you Google "tick stick", it may give you some ideas for a way of getting some measurements to use to with your paper template so that you can double check things before you cut your ply.
Click to expand...

+1

I have experience of working with large paper documents in an environment where dimensional stability was important. Ordinary paper is dimensionally unstable and expands and contracts by different amounts in different directions (across/along the roll). In the worst case, you are looking at changes in dimensions of up to a centimetre per metre with changing temperature/humidity (that was Soviet maps printed on something like newsprint!). Shifts in the order of a few millimetres per metre would not be surprising, and you would be surprised how fast paper changes its dimensions.

Of course, there are solutions - buying specialized stable paper or plastic being the best. Your best source of such paper will be paper suppliers for drawing offices; they will supply wide rolls of stable media for use on large format inkjet plotters. You can expect prices in the region of £100 for a 60" wide roll - perhaps less as you don't need any great length. You might get large sheets, but the maximum size is likely to be A0, and you'll probably have to buy a packet of at least 25 sheets. Your local quick print bureau might be willing to sell you a few metres, if they keep suitable stock (which they probably will, to service small drawing offices).

I'd recommend using a mylar drawing film - totally dimensionally stable, waterproof and very tough; you can't tear it easily. It should be readily available in most parts of the world.
 
I covered my worn out and dark bulkheads with white two pot painted 4mm ply.In your case they would be varnished.It changed the boat overnight.If you don't mind making the change permanent glue them with dabs of CT1 or similar..I didn't so used small stainless screws around the perifery . A book rack on the port side and an oil lamp on the starboard side were screwed throught the 4mm ply to the bulkheads which helped.The screws are hidden by the wooden trims around the bulkheads.I made very accurate templates with thin wooden battens screwed together that radiated from a central piece of plywood.
boat1.jpg
 
That's a fine piece of work 30boat.

I think white bulkheads and cabin sides, with varnished hardwood trim, look much better than the usual dreary acres of varnished plywood, and they make the interior much lighter.

If I was the OP I'd be tempted to repair the bulkhead and then paint it white.
 
I seem to recall an article in PBO on veneering all sorts of shapes. Basically the veneer was positioned onto epoxy and pressed down with a roller to ensure even pressure, the grab was sufficient to hold the veneer in place even on vertical faces, although joins were Sellotaped over until fully cured. It was all rather similar to wallpapering and can include techniques such as overlapping edges, cutting along a straight edge and then removing the unwanted pieces to achieve a perfect join.

I have seen a bulkhead wallpapered on a boat I was considering buying, I'm glad to say the new owner stripped it off and made good. White Sadolin Superdec has been recommended to achieve good opaque finish for internal surfaces.

Rob.
 
My experiments with veneer make me regard it as something mostly best left to skilled people in good workshops.
If the OP can make a good job of it on vertical surface working aboard a small boat, he will have my respect.
I can let small bits into damaged areas, but big bits of veneer tend not to lay flat.
Not for me anyway!

If going the ply route, how will the edges be finished?
If it involves a hardwood moulding, perhaps this is an opportunity to hide a few small fixings which keep things in order while the glue sets.
Some cunning use of clamps and boards to spread the pressure should be possible?

I like the mix of light painted surfaces and contrasting hardwood by the way.
 
Thanks again for the replies.

The flooring adhesive I referred to is in fact thixofix but arrives in 20 litre tubs for about €60.00, I used it previously to bond stainless steel to mdf and many other unusual combinations.

I really like the white bulkheads and would be tempted, but,the boat is a HR and is going on the market soon, many potential buyers in the past were obsessed with this satin finished mahogany and to be fair at night with the soft lighting it has a certain appeal.( my next boat, which is a project at the moment will have painted bulkheads with hardwood trims.)

The paper I intend to use is strong and seems plasticized, in any case it is very hard to tear, it came from marketing stands where it fitted exactly into frames, therefore it must be dimensionally stable, in any case I have the ability to trim one side which will not be seen and some of the top which is covered by trims and, if needs be I can fit a trim over the last edge.
 
How about vacuum bagging? I have no experience of it but there's plenty of information about it on the internet.

If I was re-panelling a bulkhead I would try and subdivide the area into more easily handled panels and cover the joints with d-shaped teak mouldings.

By the way, I have a book here called 'Boat Joinery & Cabinetmaking Simplified' by Fred P. Bingham. He warns against assuming that boats are symetrical. In other words, if you make an accurate half-template for one side of the boat don't assume that it will exactly fit the other side!
 
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I am aware that one side will not necessarily fit the other.

Breaking up the panel will destroy the object of the exercise. (i.e. to replicate the original finish, appearance)

I am a carpenter/joiner by trade so I will probably manage the carpentry, the glue situation is resolved, I am going to use thixofix (flooring adhesive).

Photos of finished job in a few days.

Regards.
 
pandos said:
I am aware that one side will not necessarily fit the other.

Breaking up the panel will destroy the object of the exercise. (i.e. to replicate the original finish, appearance)

I am a carpenter/joiner by trade so I will probably manage the carpentry, the glue situation is resolved, I am going to use thixofix (flooring adhesive).

Photos of finished job in a few days.

Regards.
Click to expand...
Yes please let us know how it went!
 
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