White River Hardwoods · MDF Radius Corners · Made in the USA
4″ Econo Quarter Round
SKU 4ECQ58 · Accepts 5/8″ Plywood · 4″ Radius · 97″ Length
Double Refined MDF · 5 11/16″W × 1 5/8″D · Ships LTL
Where bent plywood fails and kerf-cut corners fall short, the 4ECQ58 delivers a true 4″ radius in Double Refined MDF — consistent, paintable, and manufactured to spec every time. Accepts 5/8″ plywood box construction.
Where bent plywood gaps and kerf-cut corners crack, the 4ECQ58 holds its radius cleanly — Double Refined MDF, milled to spec, every piece the same.
Product Details
Dimensions & Specifications
| SKU |
Profile |
Radius |
Accepts |
Width |
Depth |
Length |
| 4ECQ58 |
Econo Quarter Round |
4″ Radius |
5/8″ plywood |
5 11/16″ |
1 5/8″ |
97″ |
* Material: Double Refined MDF. Lead time: 7–10 business days. Ships LTL — minimum $45 freight. Street address required for delivery.
Why MDF Radius Corners
The Problem This Solves
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Econo Quarter Round — 4″ Radius
The Econo Quarter Round profile provides a clean radius transition at cabinet and furniture corners. The quarter round geometry wraps the corner fully — no exposed substrate, no raw edge, no gap.
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Double Refined MDF
Double Refined MDF machines cleanly, paints to a flawless finish, and holds its shape over time. No grain inconsistency, no void risk — just a consistent, dense substrate that takes primer and paint the way cabinetry demands. A surface indistinguishable from solid wood when properly primed and painted.
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Only National Manufacturer
White River Hardwoods is the only national manufacturer of MDF radius corners in the USA — made in Fayetteville, AR. Consistent quality, reliable availability, and a supplier that has been delivering to the cabinetry industry nationally for decades.
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Accepts 5/8″ Plywood
Engineered specifically for 5/8″ plywood box construction — the standard substrate for this profile. The plywood box butts cleanly into the radius corner without shimming, scribing, or custom fitting. One piece, right the first time.
Installation
Working With Radius Corners
1
Plan Your Layout
Determine the location and orientation of each radius corner. The piece is 97″ long — cut to your finished height. Mark cut lines accurately before cutting; MDF does not forgive mis-cuts at visible faces.
2
Cut to Height
Cut with a fine-tooth carbide blade — MDF dulls blades quickly. Cut from the finish face to minimize tear-out. Support the full length when cutting to prevent binding and chipping at the cut line.
3
Dry Fit First
The 5/8″ plywood box should seat cleanly into the radius channel. Dry fit before applying any fasteners or adhesive — confirm seating depth and check that the radius face is flush with adjacent cabinet faces.
4
Fasten & Secure
Secure with construction adhesive and finish nails or screws through the cabinet box. Pre-drill to avoid splitting. Set fasteners slightly below the surface — MDF fills cleanly and holds fasteners well when properly pre-drilled.
5
Fill & Prime
Fill all nail holes and seams with lightweight filler. Sand flush when dry. Apply a quality MDF primer before finish coats — MDF is highly absorbent and requires a sealing primer coat for a smooth, paint-ready surface.
6
Finish to Match
Apply your chosen paint in thin, even coats over the primed surface. Two finish coats over primer is standard for a smooth painted cabinet finish. Sand lightly between coats with 220-grit.
Always Prime MDF Before Finishing
MDF is highly absorbent at cut edges and faces. A quality MDF-specific or high-build primer is essential before any finish coat. A properly primed MDF radius corner paints to a finish indistinguishable from solid wood — skipping the primer step results in an uneven surface that requires significant additional work to correct.
Shipping — LTL Freight
MDF Radius Corners ship via LTL freight. Freight is calculated by destination with a minimum charge of $45. If actual freight exceeds $45, a separate freight invoice will be emailed after your order is placed.
Important: LTL delivery requires a physical street address. We are unable to deliver to APO/FPO addresses or PO Boxes. Estimated lead time is 7–10 business days from order confirmation, subject to inventory availability.
4ECQ58 — 4″ Econo Quarter Round Radius Corner. The one the cabinetry industry keeps coming back to.
