Thread: Help - CA problems

I've done this before and it's probably not the quality of the CA. I think you maybe pressing the parts to together too hard. This causes the ends of the turned portion too much stress therefore the CA begins to crack/separate. Try using some high density plastic as a barrier between whatever your pressing the parts together with. I use some hand clamps (see pictured below), the plastic caps are kind to your pen and you can use gentle pressure to assemble your pens.

Originally Posted by Scott

I've done this before and it's probably not the quality of the CA. I think you maybe pressing the parts to together too hard. This causes the ends of the turned portion too much stress therefore the CA begins to crack/separate. Try using some high density plastic as a barrier between whatever your pressing the parts together with. I use some hand clamps (see pictured below), the plastic caps are kind to your pen and you can use gentle pressure to assemble your pens.

Thanks Scott, I'm not applying that much pressure and the chips sometimes start during the press up, even the transmission so I'm really scratching. I have tried the high density plastic on others not on the CA though so will give it a go. I'm thinking I will stick to the 30% Wattyl Stylwood finish.

Could also be that if the fittings are tight either from manufacture or if a bit of glue residue etc is left inside the tube, as they are pushed in it is forcing the turned blank to expand slightly and causing cracks in the finish.

cheers
WH

Originally Posted by wood hacker

Could also be that if the fittings are tight either from manufacture or if a bit of glue residue etc is left inside the tube, as they are pushed in it is forcing the turned blank to expand slightly and causing cracks in the finish.

cheers
WH

Thanks WH, I prefer to use 24hr Araldite & pay particular attention to the cleanup of glue in the barrel with Metho & cotton buds at assembly well before it gets a chance to set. So I'm not sure it glue residue or tight fittings either because it doesn't happen with Stylwood NC lacquer & Minwax WOP finishes?

Moby

It seems the problem is you are not squaring off the ends of the blanks after applying CA. This will leave a CA ridge on the end and cause it to lift when under pressure while assembling the pen.

You can use delrin bushes for applying the CA after you have turned the pen using metal bushes. Delrin is the material cutting boards is made from. You can make your own or do a web search and get some from the US. They are not expensive and you only need one set for all pen sizes. The CA won't stick to the delrin as it will to metal bushes, thus you will be able to get them off the mandrel easier.

Before you assemble the pen you have to square up the end of the blank to remove any CA and to ensure the fit is perfect.

https://www.woodworkforums.com/f69/sq...-blank-150926/

Have a look at the above post at the system dai sensei uses to square off the blanks. I copied his and use a similar system but because I don't have a metal lathe, I just glued a piece of 7mm drilled round timber over the end of a shortened (sawn off) mandrel using Sika Poly glue. I then used stick on velcro on the timber to hold the 240 grit sandpaper to the timber. You can buy small sanding discs with velcro on the back from Timberbits or McJing Tools. I think you can even buy the pre-made pad to hold the sandpaper in place from them too. Anyway, I put the sandpaper mandrel in he headstock and another mandrel in the tailstock of the lathe. Then put the blank onto the tailstock mandrel. Turn on your lathe and move the blank towards the sand paper and rotate it gently by hand. The sandpaper will remove any excess CA from the end of the blank and square it up at the same time. Assembly should then not be a problem.

Hope this helps

Moby,

Happy New Year !!
A photo or photos may also help with identifying what is going on.

Cheers
Tony.

Originally Posted by plantagenon

Moby

It seems the problem is you are not squaring off the ends of the blanks after applying CA. This will leave a CA ridge on the end and cause it to lift when under pressure while assembling the pen. Have a look at the above post at the system dai sensei uses to square off the blanks.
Hope this helps

Originally Posted by AuS MaDDoG

Moby,

Happy New Year !!
A photo or photos may also help with identifying what is going on.

Cheers
Tony.

Thanks guys,
I think its the squaring off that I may not be paying sufficient attention to on some of them & I like the simple jig to touch up the ends. Maybe the WOP & NC lacquer are just more forgiving. I was thinking of a bar mounted something like the Heligrind jig to flip over & sand in a similar manner but this is a KISS solution with gear I already have.

There are a few main issues causing separation at the ends:

1. CA/glue inside the tube making the fit too tight - ensure completely clean
2. Blanks ends not square, or fitting put in on angle, either way causing the parts to skew off alignment - square off blank properly and ensure parts are pressed in carefully to ensure they remain square
3. Parts not made to fit properly - file out tube to ensure good fit
4. CA finish stuck to bushes and releasing them by simply breaking - I use Delron cone bushes whilst applying CA, but even more importent is scoring the CA with extremely sharp tool edge, so the bushes separate easily.
5. Moisture under the CA finish - ensure blank dry and do not wet sand until blank is completely sealed, including the ends! Many people trim the ends but forget to reseal them before final finishing/polishing.

Originally Posted by dai sensei

There are a few main issues causing separation at the ends:

1. CA/glue inside the tube making the fit too tight - ensure completely clean
2. Blanks ends not square, or fitting put in on angle, either way causing the parts to skew off alignment - square off blank properly and ensure parts are pressed in carefully to ensure they remain square
3. Parts not made to fit properly - file out tube to ensure good fit
4. CA finish stuck to bushes and releasing them by simply breaking - I use Delron cone bushes whilst applying CA, but even more importent is scoring the CA with extremely sharp tool edge, so the bushes separate easily.
5. Moisture under the CA finish - ensure blank dry and do not wet sand until blank is completely sealed, including the ends! Many people trim the ends but forget to reseal them before final finishing/polishing.

Thanks DS
1 may be an issue
2 Ive checked that but MD & WH have given me some tips.
3 will check.
4 Ive scored the CA carefully.
5 definitely very dry but I did use Wattyl Readi Seal as a sanding sealer because I was going to use Stylwood. Sanded most of that off though.

After taking on board many of your helpfull comments here are the results so far. Not sure what the timber in the lhs set is - its a WA timber. The rhs set is an unknown palm.

Palm Slimline CA.jpg

got to be happy with them, all look good.