Cutting purfling after gluing

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Enrico Schiaffella
Posts: 44
Joined: Tue Aug 28, 2012 9:46 am

Cutting purfling after gluing

Post by Enrico Schiaffella »

I decided to try a different procedure for making the purflings. I cut each strip extra large, about 1”. I glue them directly bent in the mold. The result is nice. I get this nicely bent purfling. The good thing about this is that I can make complex purfling. Much more than a couple of black white black lines. But now the problem. I have to cut bent purfling which is not easy. I tried to cut it on the drill press with a small circular saw. It worked but results were so and so. Can you please suggest a successful way of cutting this purfling? I was thinking on the band saw but I am afraid I might break it especially at the waist where there is no support below the wood.
Thanks Enrico

Bob Orr
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Location: Nailsea, Nr Bristol, UK

Re: Cutting purfling after gluing

Post by Bob Orr »

I presume you have made extra wide purfling and bent it and now trying to cut them down to width? That is why people cut them before they bend them! Almost impossible to support the waist area however you cut it.

Enrico Schiaffella
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Joined: Tue Aug 28, 2012 9:46 am

Re: Cutting purfling after gluing

Post by Enrico Schiaffella »

Yes I think you are right. I can't see a way of cutting it, if not by using the drill press and the small circular saw I was talking about before. Maybe I might try to make a rudimentary outside form with some scrap wood just at the waist area to support it. But I don't know if it's worth it. That's why I am asking you guys

Carl Dickinson
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Location: Forest Ranch, California

Re: Cutting purfling after gluing

Post by Carl Dickinson »

I made an inside/outside caul for gluing up solid linings with 3/4 MDF, similar to inside and outside mold pieces with a little more space in between that clamps the pieces between. Something like that could be used to trap your glued up piece, extending an edge out the width you want plus the bandsaw blade width. The slice it off flush with the face of the caul. I'd probably put a foot on the caul to help keep it parallel with the blade. I don't know for sure if this would work, just musing.....

Enrico Schiaffella
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Re: Cutting purfling after gluing

Post by Enrico Schiaffella »

Yes I was also thinking something like that. Tomorrow I will decide And cut. As soon as I have The results I will let you know.

Clay Schaeffer
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Re: Cutting purfling after gluing

Post by Clay Schaeffer »

I have glued up purflings in that fashion and cut them on the tablesaw with a thin kerf blade raised all the way up. You have to hold down the waist portion of the layup. When I have done that I have made a layup that is several inches wide. That Is how I trim side set layups. If I were to do one that is only an inch wide I would hot melt glue a thin "handle" on the waist portion that would be progressively be sawed off as the strips were cut. This would help keep your hands out of harms way. It is still a little dicey.
If you have an oscillating tool you could overhang the lay up on the mold and use the edge of the mold as a guide for a half moon blade on the oscillating saw. Slower but safer.

Enrico Schiaffella
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Joined: Tue Aug 28, 2012 9:46 am

Re: Cutting purfling after gluing

Post by Enrico Schiaffella »

Thanks Clay. I am a bit scared to do this operation on the table saw. But your suggestion is very appreciated. Thanks

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Barry Daniels
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Re: Cutting purfling after gluing

Post by Barry Daniels »

Some things just have to be done first. Cut before bending.

I cut the strips, glue, then bend. There is no perfect method, but this one seems to work best for me.
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Enrico Schiaffella
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Joined: Tue Aug 28, 2012 9:46 am

Re: Cutting purfling after gluing

Post by Enrico Schiaffella »

I think you are right. I think this is what I will do from now on. It all depends on how the cut will go. I fear for the worst though.

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Barry Daniels
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Re: Cutting purfling after gluing

Post by Barry Daniels »

Purfling is really thin so aggressive tools like table saws can be overkill unless you take some protective measures like zero-clearance inserts and hold downs. I cut purfling with a utility knife and a metal straight edge. Less stress and waste.
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Clay Schaeffer
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Re: Cutting purfling after gluing

Post by Clay Schaeffer »

Hi Enrico,
As I mentioned cutting purfling strips on a table saw can be pretty "dicey". It is something I have done, always keeping my hands well away from the blade. But I am pretty familiar with using the tablesaw (shapers are something that I don't have much experience with and are a bit scary to me - they are like routers on steroids)
Never do something you feel is unsafe - because it probably is.
The oscillating tool would be a safer method, but a bit slower.

Carl Dickinson
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Location: Forest Ranch, California

Re: Cutting purfling after gluing

Post by Carl Dickinson »

You could also use Clay's idea of a oscillating tool instead of a bandsaw with the inside/outside caul system. That would probably work best of all to salvage the work you already have in that piece.

Clay Schaeffer
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Re: Cutting purfling after gluing

Post by Clay Schaeffer »

While I was in the shop today I found some purfling offcuts that I had molded some time ago. When I cut them on the table saw I usually have some of the layup left over (I only let my fingers get so close). Carl's idea of using the the bending form and mold as an inside/outside clamping caul would probably work better than what I did (it might be easier to align the work).
But here goes - the first picture shows the off cut clamped to a bending form using f body clamps. I tried using rubber bands but that was a "fail". the second picture shows the smal lwhite spacer blocks that set the width of the purfling strips. That was the most finicky part of the process, and where what Carl has suggested may make things easier.
Attachments
osc purf 1.jpg
osc purf 2.jpg

Clay Schaeffer
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Re: Cutting purfling after gluing

Post by Clay Schaeffer »

The oscillating tool with a half moon blade is held flat on the bending form and saws through the purfling layup. The half moon blade allows you to keep cutting even as the blade meets the work at varying angles. I also allows you to cut "under" the clamps.
When I switched to the mold the layup was originally molded with I found I could use less clamps and set things up easier. D'oh!
Attachments
osc purf 3.jpg
osc purf 4.jpg

Clay Schaeffer
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Re: Cutting purfling after gluing

Post by Clay Schaeffer »

That oscillating tool is the single speed model HF has for $20. I also have a couple of the variable speed models ($34) which I like much better. After HF came out with the Fein multi-tool clone a number of other makers have come out with versions of the oscillating tool.

Carl Dickinson
Posts: 53
Joined: Fri Feb 08, 2019 5:38 pm
Location: Forest Ranch, California

Re: Cutting purfling after gluing

Post by Carl Dickinson »

Here's the caul/jigs I used for gluing the solid linings, melamine over particle board. Lined the edges with packing tape to resist the glue. Holes are for clamps.
IMG_20200429_161438_3.jpg
Not pertinent to this thread, but now I glue the strips up for the linings per a description by Bryan Bear. Somewhere, maybe here, or OLF.
Tell us how it worked out Enrico. :D

Clay Schaeffer
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Re: Cutting purfling after gluing

Post by Clay Schaeffer »

Hi Carl,
You could probably use those same jigs for gluing up purflings and bindings if so desired. The small amount of "off set" shouldn't be a problem.

Enrico Schiaffella
Posts: 44
Joined: Tue Aug 28, 2012 9:46 am

Re: Cutting purfling after gluing

Post by Enrico Schiaffella »

Thanks to all for the nice suggestions. I want to give you an update. I did it on the bandsaw. I glued a sacrificial mold just at the waist area. It only took 5 minutes to build and it turned out perfect. Yes, it can be done on the bandsaw quite easily. I didn’t feel there was a time when I risked doing some damage. The only problem so far is dealing with even thickness. That can be the weak part of the process. But as we all know, usually when you try alternative routes, you make life easier at a certain point and discover that you have troubles somewhere else. Sometimes there is not a perfect way of doing things but something that works for someone and doesn’t for others. In this case I am not completely happy mainly because I have to spend some time to thickness the purfling. And the results are not perfect. I could obviously make up some jig to cut it more precisely. Probably it can be done.

Enrico Schiaffella
Posts: 44
Joined: Tue Aug 28, 2012 9:46 am

Re: Cutting purfling after gluing

Post by Enrico Schiaffella »

FD39F5BD-5A40-4C17-9F86-A48EEDEA922B.jpeg
Thanks to all for the nice suggestions. I want to give you an update. I did it on the bandsaw. I glued a sacrificial mold just at the waist area. It only took 5 minutes to build and it turned out perfect. Yes, it can be done on the bandsaw quite easily. I didn’t feel there was a time when I risked doing some damage. The only problem so far is dealing with even thickness. That can be the weak part of the process. But as we all know, usually when you try alternative routes, you make life easier at a certain point and discover that you have troubles somewhere else. Sometimes there is not a perfect way of doing things but something that works for someone and doesn’t for others. In this case I am not completely happy mainly because I have to spend some time to thickness the purfling. And the results are not perfect. I could obviously make up some jig to cut it more precisely. Probably it can be done.

Enrico Schiaffella
Posts: 44
Joined: Tue Aug 28, 2012 9:46 am

Re: Cutting purfling after gluing

Post by Enrico Schiaffella »

Another picture
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0994E6FC-B6E8-456B-BAA0-310B836CD6CF.jpeg (15.37 KiB) Viewed 2015 times

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