Spoilboard Ideas?

[Steve355Participant @steve355]

<p style=”text-align: center;”>Hi</p>
For my projects I often find myself profiling, chamfering and engraving brass sheet (0.9mm recently). To do this I’ve been using a chipboard spoilboard I guess 3mm thick. See video.

Problem is, however careful I am, when screwed down to the bed with this material in between, the brass isn’t remotely flat, and remains springy at the edges.

does anybody have any ideas for a spoiler board material that is less compressible, and very cheap? I thought of using cheap vinyl floor tiles or something but I haven’t yet come up with a brilliant solution.

ideas welcome!

Steve

 

 

[Andy StopfordParticipant @andystopford50521]

How about using that hot melt glue that comes in sheets?

[Wal WerbelParticipant @walwerbel59154]

I also CNC cut thin sheets of brass and alu, quite often I need to run a round-over end-mill along the edges, so flatness is important.

I screw down 18mm MDF to my bed and surface it.

I then apply 50mm wide 3M masking tape to the back of the plate and also to the freshly surfaced MDF (dust removed, obvs).  Super glue then applied in thin beads along the lengths of the masking tape, plate positioned and weighted down using another flat bit of MDF along with several 20-odd-kg handled weights (shown in the last pic aiding a wood gluing effort).

[John HaineParticipant @johnhaine32865]

I generally use MDF with the 2-tape and superglue approach mentioned by Wal.  A nicer material that I have some offcuts of is “”Valchromat” which is denser, has a smaller grain, and flatter.  If you are careful with DOC an alternative is to glue down on a single layer of 3M blue masking tape on metal, so the DOC just gets through the metal.  Then boil to release the part.

[BazyleParticipant @bazyle]

First post said “see video” but I don’t see link. Are you using a board on top of the sheet?

[Wal WerbelParticipant @walwerbel59154]

Indeed – Valchromat is lovely, but I haven’t been fortunate enough to have any larger offcuts come my way.

Metal to metal before boiling off works great when you need a stronger bond, ie. for milling fiddly shapes where a lot of the glued area gets removed.  Just don’t glue over any screws that you may need to get to in order to remove the sacrificial bit of metal – that ol’ chestnut I know so well…  😂

OR direct (no tape) to hardwood worktop off-cuts like in the image below – once done you can dab on acetone which will degrade the super-glue and let you release the work without needing to use too much force.

[JasonBModerator @jasonb]

I also us eMDF, Melamine faced or just plain depending on what offcuts I have at the time. Masking tape to the board and back of th emetal then superglue the two tape surface stogether.

Get your DOC right and you don’t even spoil the spoil board as you can just partly cut into the layers of tape.

 

[John HinkleyParticipant @johnhinkley26699]

When using my Shapeoko router, I found that for cases such as these and where it wasn’t either possible or desirable to use clamps, 3M Super Sticky clear tape worked well.  So well, in fact, that it was often difficult to remove the workpiece from the sacrificial board.  Not impossible, but it needs to be used sparingly.  One source is on eBay, here.

Not the seller I used, but has a wide selection of widths, lengths  and colours.

John

 

[Steve355Participant @steve355]

Sorry, video was too big to upload , even when I made it small. Pic below instead.

I have tried the superglue/ double side tape approach in the past and it would not reliably stick. Perhaps it was the substrate I was sticking it to – which was probably

Imagine doing several of these a day… I thought it would be easier to drill a spoilboard and the workpiece and bolt it on. No tape to put on or clean off etc.

 

 

 

[DalboyParticipant @dalboy]

For many jobs I use the dividers from toilet cubicles (Washed first) It is about 1/2″ thick and very solid and does not bend easily. That is if you can find somewhere they are refurbishing some. Mine came from a school; that was having work done.

It machine well as I have just made a part from it.

 

The cut edge was done with a circular saw

 

[BazyleParticipant @bazyle]

So what is that board made from? Is it a solid perhaps plastic impregnated wood, or a good quality board with a thick plastic layer? Is it machinable – I’m thinking other uses really.

[JasonBModerator @jasonb]

CGL Compact Grade Laminate, think of thick Formica and you get the idea

[JasonB]

On JasonB Said:

CGL Compact Grade Laminate, think of thick Formica and you get the idea

That is the smell you get when machining it. For the best finish I found the last cut need to be a very shallow cut for best results

[DiogenesParticipant @diogenes]

I recently had some brass panels cut, the guy also used the same process as Wal and Jason – normal single-sided 50mm masking tape on top of board and back of stock, then stuck one on top of the other with lengthwise beads of superglue (and a quick spray of activator).

Edit – straight onto MDF after blowing the dust off with airline

[Steve355Participant @steve355]

Right, I had another go at this today. I bought a plank of MFC from Wickes, and drilled it for mounting on my CNC bed.

I realised that previously I had used double sided tape rather than the masking tape and superglue method. That worked really well.

Plus I cut the O1 dry, which worked very well.

 

[Steve355Participant @steve355]

Just coming back to this topic after more failure.

I’ve done this quite a few times (tape & superglue) and it has worked ok. But the problem is, burrs on the underside of the brass are approx 1/2mm thick and cause the brass plate to delaminate from the spoil board. Once even slightly loose, the problem gets quickly worse.

It may be a way to deal with a single profile on a sheet, but when there are many, I’m not convinced it is practical.

[John HaineParticipant @johnhaine32865]

What grade brass are you using?  I profile 1.6mm engraving brass with no problem and little burr.  I only just cut through the metal by 0.1mm or so.  “Softer” brass I can imagine would burr badly.

[JasonBModerator @jasonb]

You also want a sharp cutter, if it is throwing up an excessive burr then chances ar eit ha slost it’s edge. Ones for nonferrous metals also help.

As John says the softer more golden looking brass is not as nice to machine and I would only use that if I wanted to subsequently bend it.

[Steve355Participant @steve355]

Hi

Brass is CZ108 0.9mm. True, the cutter is probably dull – been using it for a while including on O1.

I can’t do much about the brass – I have a small pile of it. But I can change the cutter.

I wonder if the spoil board is an issue. It is 1/2 inch MFC, which is quite rigid and I don’t think gives much if pushed. I moved away from softer chipboard, perhaps that was a mistake.

New cutter then.

 

 

 

[JasonBModerator @jasonb]

If it has been used on carbon steels then quite likely to have lost it’s edge.

The Melamine and even more so the C**p that is in chipboard particularly the fine outer layers can be quite abrasive. If I am doing a lot of cutting of MFC with insert router bits there are two noticable area of wear on the cutters that correspond to the top and bottom surfaces of the board.

Melamine faced MDF seems to be kinder to cutters or just go for a good quality Moisture Resistant MDF as that is a lot denser than even good quality plain MDF.

[Dave HalfordParticipant @davehalford22513]

Chipboard blunts carbide, ask your circular saw blade once you’ve cut a room full of hard flooring.

[John HaineParticipant @johnhaine32865]

“What is the difference between CZ108 and CZ121?

CZ108 is an alpha alloy. Alpha alloys are ductile and can be cold worked. Brass alloy CZ121 is used for machining – it has a machinability rating of 100 and is the standard against which the machinability of other alloys is measured. It has Lead added to the composition to improve machinability.”

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