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PurpleHeart dining table Help Please!

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Forum topic by AramM posted 04-07-2021 01:20 PM 718 views 0 times favorited 20 replies Add to Favorites Watch
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AramM

8 posts in 21 days


04-07-2021 01:20 PM

Topic tags/keywords: question purpleheart cupping purple

Guys! I’ve been on quite a journey with this purpleheart dining table. I am a musician, and hobby wood guy.

-This table is 8/4 solid Purpleheart. Glued-up from 6 boards.

-I tried everything people discussed to get the color a deep grape purple which I really wanted. Even laid in the sun for 2 days.

After nothing worked, I reluctantly reached for the heat gun as last resort. Knowing this works for sure, and knowing that heat+wood = dangerous. A lot of money and time has been poured into this thing so far. I figured I’d do small spots little by little to not put too much stress on any one glue joint.

So it’s working, the color is beautiful. Just what I wanted, BUT, the table as a whole is cupping!!

Any experienced furniture builders here have any advice? I’m halfway through roasting the tabletop, and can’t turn back now.

My theory was that I’ve been overly drying the table top, and not the bottom side, so that’s why it’s maybe cupping? If I were to lay it out in the sun upside down, would the dryness even out? and would it bend back? What can I do?

I have thickness to play with. I don’t know how deep the purple goes. If it goes deep enough I can sand the high parts and still keep the color.

Please help!! Thank you
Aram

Table Cupping…

Purplization with heat gun…

Progress so far…

I put in the c-channels hoping they would help flatten, but no…


20 replies so far

View Aj2's profile

Aj2

3773 posts in 2856 days


#1 posted 04-07-2021 02:00 PM

Of course it will cup if you heat one side. My suggestion is if the cupping is unacceptable you will need to re mill the table. I am saying rip the top back down to boards and plane them till flat. I would concentrate on the bottom.
I bet if you remove wood from the underside of the boards the top will straight out a bit .
For the color conundrum I would experiment with a purple dye . Purple Heart turns brown over time.

-- Aj

View SMP's profile

SMP

3826 posts in 964 days


#2 posted 04-07-2021 02:05 PM


.
For the color conundrum I would experiment with a purple dye . Purple Heart turns brown over time.

- Aj2

Yeah, lot of unnecessary stress for a brown table. Maple takes purple dye well if intent on a purple table.

View Madmark2's profile

Madmark2

2522 posts in 1647 days


#3 posted 04-07-2021 02:58 PM

Since its a solid top and not veneer anytime the surface goes brown just give it a little sanding and freshen up the finish. This is easy if you use a soft finish like plain paste wax.

Heat both sides evenly. Finish both sides evenly.

Did you alternate ring direction on the glue up?

Tip:
Round those corners!

-- The hump with the stump and the pump!

View avsmusic1's profile

avsmusic1

682 posts in 1743 days


#4 posted 04-07-2021 03:25 PM

just my feeling – the botchy color is a bigger issue than the cupping. I’d worry first about leveling out the color at this point.

I’m not very experienced with purpleheart but will it deepen in color on it’s own over time (like cherry)? It’s probably too late but i wouldn’t rush it if this is the natural progression. Also, if it tends to go brown (like padauk) then you could even consider coloring the finish

View CaptainKlutz's profile

CaptainKlutz

4363 posts in 2553 days


#5 posted 04-07-2021 04:06 PM

All that work for a temporary color change? No thank you.
https://www.wood-database.com/wood-articles/preventing-color-changes-in-exotic-woods/

+1 maple
This is only way I would make purple wood:

If C-channel is not stopping the cupping, then limited options exist to fix it. Likely have to rip boards into narrow widths, and attempt to balance the grain direction and stresses. The mix of flat sawn and rift sawn boards is not helping. It takes flat boards to make flat table top.

Best Luck.

-- If it wasn't for bad luck, I wouldn't have no luck at all, - Albert King - Born Under a Bad Sign released 1967

View LeeRoyMan's profile

LeeRoyMan

1691 posts in 785 days


#6 posted 04-07-2021 04:21 PM

If I was at this stage, I would get a weed burner
Flip the table over and do the bottom first. Burn in full length strokes from side to side just as if you were spraying a finish overlapping with each stroke, then final spot burning where needed to even color. I wouldn’t worry about overheating the glue joints.
Afterwards check the top and see if the cupping changed or got worse.
I have no idea what the wood will do, but when you do the top it may balance out.

Disclaimer: I’ve never done this. It’s just an idea. As I like to say, just food for thought.

View Aj2's profile

Aj2

3773 posts in 2856 days


#7 posted 04-07-2021 05:37 PM

I bet that top was close to grand. This reminds me of a post several years back a guy with very limited woodworking experience bought 2 k worth of Rough sawn walnut to make a table.
He asked to forum how to cobble together the wood without a jointer or planer. Just gotta admire the I can do anything sprit of Americans.
Good Luck

-- Aj

View Ocelot's profile

Ocelot

2977 posts in 3697 days


#8 posted 04-07-2021 06:07 PM

8/4 PH is $4.00/bf at Advantage Lumber Florida. It’s cheaper than Maple.

Should be nowhere near a grand.

-- I intended to be a woodworker, but turned into a tool and lumber collector.

View AramM's profile

AramM

8 posts in 21 days


#9 posted 04-07-2021 06:40 PM


Of course it will cup if you heat one side. My suggestion is if the cupping is unacceptable you will need to re mill the table. I am saying rip the top back down to boards and plane them till flat.
- Aj2

My blood pressure is rising! Seriously, I’m really grateful for all of you jumping in to help. This is where my inexperience shows.

I don’t think it’s bad enough to re-cut the boards and start from scratch. At least I want to try some science first to help it go back.


Heat both sides evenly. Finish both sides evenly.
- Madmark2

This is what I wanted to hear! Thank you Madmark2. This is what I want to pursue. It doesn’t need to be perfect, I just need it to go back enough to where an average person wouldnt confuse it for a skateboarding half-pipe. The table is for my own home, not a client.


All that work for a temporary color change? No thank you.
https://www.wood-database.com/wood-articles/preventing-color-changes-in-exotic-woods/

+1 maple
This is only way I would make purple wood:

- CaptainKlutz

I was really drawn to the color that purpleheart can look at it’s best. That was why I started this table.

Look at this color here!
https://youtu.be/p6kf_PIu3GU?t=190

So I really wanted the natural color. Dying another wood purple, to me wouldn’t look as elegant and might look a little more whimsical.

I know it browns after (5 years I think). That’s why I got the thick boards, My plan was to re-sand and finish again in 5 years. Working with this wood was just something I had to do.


8/4 PH is $4.00/bf at Advantage Lumber Florida. It s cheaper than Maple.
Should be nowhere near a grand.

- Ocelot

Yikes, I should’ve rented a van and gone to FL. I live in CA, and I paid a lot more than that! Well over a grand, but I have nearly 3ft cut offs from each of the 5 boards and I want to make a matching coffee table. The dining table is 48” x 80”

Anyways, Thank you all! I will keep you posted. I’m gonna put it out in the sun bottom up or heat gun and hope it goes back. Then finish roasting the top, then probably re-do the back again. This has been way more work than intended, and my wife is close to using the heat gun on me. but if it works out, I’ll be grateful.

Aram

View northwoodsman's profile

northwoodsman

526 posts in 4805 days


#10 posted 04-07-2021 06:42 PM

I have worked a little with Purpleheart. I would not take on a large project like a table top with it. It’s too unpredictable. In the past year I included some in two different cutting boards from the same piece of 8/4 Purpleheart. The wood from one end developed little hairline cracks all over the surface within a few weeks, while wood from the next section was just fine even after 6 months. The piece had been in my shop for well over a year. I remember when I was going through a large stack of it at the lumber supplier there was a substantial variance in color from one piece to the next, even from one end to the other. I have never seen Purpleheart look like it does in that video, if I didn’t know better it looks like he is spraying purple dye on it. But if it’s on the internet, it has to be real.

-- NorthWoodsMan

View AramM's profile

AramM

8 posts in 21 days


#11 posted 04-07-2021 06:45 PM

As for the blotchy color. It is hard to get a consistent color with the gun, but one swipe of 600 grit, and the charred particles go away and gets way more even. I think the color will be good in the end.

View SMP's profile

SMP

3826 posts in 964 days


#12 posted 04-07-2021 07:07 PM



Look at this color here!
https://youtu.be/p6kf_PIu3GU?t=190

So I really wanted the natural color. Dying another wood purple, to me wouldn t look as elegant and might look a little more whimsical.

- AramM

I think a purple table is going to look whimsical whether its painted, dyed, or made from purple legos. Its a purple table! Personally i would just do whatever is easiest and doesn’t require refinishing every couple years.

View AramM's profile

AramM

8 posts in 21 days


#13 posted 04-08-2021 09:36 PM

Fair enough.


I think a purple table is going to look whimsical whether its painted, dyed, or made from purple legos. Its a purple table! Personally i would just do whatever is easiest and doesn’t require refinishing every couple years.

- SMP


View AramM's profile

AramM

8 posts in 21 days


#14 posted 04-12-2021 05:24 AM

UPDATE on the drama*

Did a lot of reading, and feeling deep regret for attempting to burn a perfectly flat tabletop that I paid so much money for…

Everything pointed to the heating and drying of one side caused the table to cup upwards. I first tried some mild ways to dry the other side in hopes I would see slow progress bending back. I plastic wrapped the top side flipped it and then left a large fan blowing on it for days…..Nothing.

I clamped it and forced it flat, and left it in the sun….Nothing.

I tried to use a light touch with the heat gun. (Not enough to change the color) to dry….and wait for it…. Nothing.

Feeling deep regret, shame, and out of options, come monday, I was gonna take it to a pro whos got a CNC, and have him flatten it, probably having to remove up 1/4” along each side.

Then I remembered what Madmark2 said here…


Heat both sides evenly.

- Madmark2

I figured ‘what the hell’ I should at least try to burn the bottom side purple the exact same amount I did the top. I so took the gun and burned the heavily cupped zone on the underside, turned it purple while it was clamped straight. Then and got a beer, and started rethinking my life.

30 minutes later, I went out to bring the table inside, and clamps just SLID off! I couldn’t believe it! It worked! With burning the underside, I am able to surgically pinpoint the exact spots that are warped and bend it back! The table is almost perfectly flat now! There was 1/2” of a dip in the middle before. Just thought I’d share.

Now I have to make a decision, to finish burning the top, (then likely re-burn the bottom.) OR Sand off the purple I have done and finish the damn table.

Am I right to assume the clamps played a huge role in this? I am now thinking if I burn the top while clamped flat, it will not warp. I think the heat gun loosens the wood and it can be forced to re-tighten in a shape by clamp pressure, and stay that way? Do you guys know this to be true?

Here’s a guy filming this in action really quick. This is what I did….
https://youtu.be/jWDQGhLv-_k

All of you critiquing the purpleheart choice…are right. After doing this process. It seems like chasing these exotic bright colors is an amateurs game. But I am where I am.

View CaptainKlutz's profile

CaptainKlutz

4363 posts in 2553 days


#15 posted 04-12-2021 01:34 PM

Do not beat yourself up to much. Nothing wrong with using Purple Heart with proper expectations.
Plus it is fun to use/learn about different woods.

Some projects make you stutter and drool when you see Purple Heart used:
Click for details

Your table will probably be stunning as well. :)

-- If it wasn't for bad luck, I wouldn't have no luck at all, - Albert King - Born Under a Bad Sign released 1967

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